I am a Certified Archivist and I consult on LTDP (Long Term Digital Preservation). Most of the "solutions" that people offer are great for the short term but really how will you deal with a 50 year or longer strategy to preserve your photos? Each solution offers some measure of preservation but no one solution is foolproof offering 5 nines - 99.999% reliability. As dirtfarmer pointed out so-called "hard media" (CDs and DVDs) have a tendency to fail. I have seen that in climate controlled circumstances. Sectors fail.

Any long term solution will use a combination of strategies along with geographic separation. You can have five back-up drives and DVDs but if your home burns you will lose it all at once. Cloud can work until you provider goes under while you are on vacation in a remote part of the planet and you did not have time to download. Anything WILL fail.

So I recommend a combination of strategies. I use cloud (Amazon currently) along with five 3 - 5 Tb drives synchronized and separated by geography. I use DVDs for some photo shoots. I also recommend saving the SD cards. You can use a safe deposit box for one of your drives but remember - drives fail. I purchase a new one about every six months. I currently store about 3 Tb of photos. I use a synchronization software to make sure all of the repositories are equal. I recommend also a vigorous metadata scheme to be able to find photos in the repository. I describe the photo sets in text files easily searched.

Whatever you do remember that each of the repositories is prone to failure of some nature. You need to have a migration strategy to move the repository forward and provide for a potential failure of that migration. Bit parity check software may be needed.

In my experience the single point of failure for most is having all the backups in one place. Fire, flood or other natural disaster will get all of the repository at once. Cloud can avoid this but go the extra step with an off site backup. I have failures and it is no problem. I move to the next repository.

I also keep my old retired drives. Once I found a segment of photos missing and found them on an older retired drive. You can never be too careful when preserving digital content.

I scan them at a very high resolution then use MS Paint. I replace pixels. While it takes a very long time I get very high resolution results without sacrificing image quality. Many programs blur or change the original character of the photo.

I am asked the question frequently, "Wasn't taking that photo risky?" Yes it was. I have been detained, my photos deleted in some very difficult circumstances. It was worth it. North Korea can be trying and you constantly know that you are minutes from detention. You need people skills to read the guides and know the "soft" rules and the "hard" rules. In the old USSR you had to be discreet. Bridges and certain buildings could not be photographed but with film they did not know what you had shot and had to catch you in the act. I spent a day in a jail and they destroyed my roll of film but I was able to resume photography. Ironically in 1990 shortly after the coup the police in Moscow were accommodating to photographers and would move us to favorable places to shoot the protests from. Yet even today in Russia I am questioned when photographing certain buildings or railways (vestiges of the old days?).In the West Bank the Israeli police would search and ask questions years ago in some areas. When lecturing I do not recommend anyone doing what I do. To be honest I think the most dangerous places are not war zones but impoverished areas of the developing nations. Hire a good driver!

I had a similar decision to make and because I did more sunsets, landscapes and occasional cropping I went with the 5DS R. It has taken me a bit longer to know how to use it than I expected but I am very satisfied with the quality of images. I think it is true that the higher megapixel cameras are more prone to blur. I do not think this is the camera for shooting action but I may have to give it a try.
I did get a payment from a photo book project so that helped offset the cost.

Because of the wide variety of options I have been forced to look at the kind of photography I am doing and find the best tool. My T2i was getting on in years and so I looked at what was available. I am doing travel photography, sunsets and I am cropping. I definitely needed more megapixels but I needed image clarity. I was pushing the limits of the T2i by increasingly using HDR to compensate for the lack of dynamic range. So I needed more megapixels and dynamic range. I was impressed with the T6s but I noticed that I was not getting the image clarity that I was used to with the T2i. I compared images and concluded the anti-aliasing was what was different. I upgraded to the 5DS R and I have been very happy with the image quality. My first photo book was published and I took the money from that and purchased the 5DS.
I do not shoot video so when comparing the Sony A7rii to the Canon 5DS R I did not care but I know some people need 4K video. I am a megapixel snob so the ability to crop is important and I know some do not mind. I looked at the 70D and the 80D and almost went with one of those. Note that some of my old EF-S lenses now are only being used on my old T2i but my EF lenses are now used on my 5DS R.
I think you need the right tool for the job. Wedding photographers would use different lenses and cameras for their specialty and outdoor photographers the same would apply.

No it is not typical and I thought nothing of it except I suggest that you test new equipment when it arrives. I buy from Canon and refurb frequently. You are right.

I purchased a T6s earlier this year and returned it to Canon. This was a refurbished model and as I was testing I found a flaw in the sensor. When I shot the sky in HDR I found large dark squares were appearing. I shot several tests and the sensor was indeed flawed - about 15% of the overall image in HDR. However, the camera was a capable one and I loved the 18-135mm lens.
That said I began to notice something that bugged me more than anything else. The anti-aliasing was too much for me. I could not seem to bypass the anti-aliasing and I found that sharpness of images was compromised. I do sunsets and landscapes with my T2i, many times in HDR but I found that the T6s was not the camera for me. A close examination of the images showed that the detail was not as fine as I was getting with the T2i. I ultimately decided against the T6s.
I have moved on to the D5S R. One of the other issues I have had is image quality suffering from cropping. That is a thing of the past with the 5DS. I am getting the clarity I want.
One thing I do notice with a 50Mp camera - you do have to take extra care to avoid a slight blur. The images are so fine that you need to take extra care. I am getting used to that (as I have had the camera for 2 weeks now) but it requires a steady hand. I travel with my cameras in some harsh environments and I put 150k images on the T2i over the last 6 years.

The probability is that the shoe box will be destroyed at some point in the future. Were you to scan the prints in the shoe box and duplicate those scanned prints either via printing or on another media the probability goes up that one of the copies will survive. Survival is often based upon the number of duplicates and where they are stored. Increase the probability of survival with duplication. Using different medial will also increase the probability of survival.

I have a Flickr account with 34,000 photos. These are a fraction of the nearly one million photos I have taken. I sell all the time and my first photo book was published in the Netherlands on the 20th of November. I print only for family or friends yet that demand is picking up due to Facebook. I will put up a sunrise or sunset and people want prints. Railroad photos are popular.
I back up my photos on six drives and cloud storage. The drives are on site and off site. Any drive failure is not a problem.
I recommend that you make your photos available in some form on the web. As I learned from Flickr I cannot judge a good photograph. People love what I think is poor and what I think is good sometimes people do not appreciate. I urge you to show your photos.

I take mine to Turkey, North Korea, Romania, New Orleans, Los Angeles and I have never had a problem. NYC? No problem.

I have used them to smuggle photos out of politically sensitive areas and they have worked well. I use an adapter and it works well but for general photographic use I use regular SD cards.

I remember people relying on Zip Disks for their photos. If you rely on any single storage media for your photos you will suffer loss. I used "archival" CD and DVD media in a climate controlled environment and 7 years later found that sectors were not reading. These were checked before putting in storage. Digital media will be preserved with multiple back ups in multiple locations. Save the cards, have a cloud backup strategy, have local storage and send a copy to a friend. Your home can be destroyed and even if you have multiple storage in your home this can be destroyed. Have a plan in the event of your death. Your photos have value and your heirs should know what to do. Take a lesson from Vivian Maier. Over time your photos will increase in value.

I am an archivist and records manager so I am over the top with this as I understand the fragility of digital objects. I have over 1.2 million photos scanned from slides and digital cameras going back over 50 years. I do keep both RAW and JPGs so that is a space hog and as I get better cameras the image size increases. I have seen digital media degrade and met all kinds of restoration issues. I buy a new drive ever six months then migrate and verify using a variety of software. We have seen a number of tragic stories of digital photo loss and I am just sure to set aside time review by various drives. One dies - no problem. They seem to last about 3 years on the average. The 5Tb drives are cheaper now and you can always take a backup to work or somewhere else for safekeeping.
Some photos are irreplaceable.

I use my car as well so you do have a measure of safety. If I go overseas for a few months I put one copy in the car. Yes, we can get to extremes and I do know some who put a copy away in a bank vault but with cloud today that can be another alternative.

So now that you have a second copy and you have a RAID array, what happens when your house burns, is flooded or is destroyed by a tornado? Move a copy of your photos either off-site or in the cloud. You can have a fool proof backup at home but you must move a copy away from your primary back up. Swap drives with a friend but be sure to keep that off site backup current. Just because you have two or three copies at home does not mean you are safe from all loss. Geography matters.