The options for the two slots in the 5D MKIV are: One card gets full and the second card starts recording.
One card records in jpg and the other in RAW. I use both cards recording in RAW.
Both cards recording the same thing, which is what I use. That has saved my backside more than once.
Go to the wrench menu then to sub menu 1 to tell your memory cards how to behave: Click on Record Function.
Standard is just choosing one card to record to.
Auto switch is one card filling and the other card starting.
Rec. separately is one does jpg and the other RAW
Rec. to multiple is both cards recording the same thing.

For sure ! Eneloop. Amazing life span. I've been using about three four packs for over five years and have never had to get more. That's using them everyday for a few hours on the job.

Interesting and curiously asked questions. Some, maybe a lot of us, through trial and error, get a way and get somewhat set in it. We find out what works for us.

Over the past fifty years when I caught the bug, I've had a Rolleiflex, five Nikon film cameras, three Nikon digitals, a Leica film camera with nine of its lenses, a Bronica, a Hasselblad, and probably a few I'm forgetting. I did interchange them depending on what I was shooting.

I loved shooting everything from people to objects to bugs, to architecture, etc. and even though I make my living with architecture and interior design now, I still love photographing anything that is interesting to me.

I got rid of all my film cameras in 2005 when I went completely digital. I loved film and fought against going away from it when the tides started turning. However, I realized that if you started using Photoshop and moved away from your darkroom, and most of the labs out there were starting to do everything digitally anyway, you were no longer "pure." That didn't make sense to me. I sold everything and went whole hog into Canon with their 1Ds MK II. Now, there would be no sense in switching around anymore since there are too many lenses involved.

I've gone through six digital Canons and always keep at least two for professional reasons.

Therefore, I would have to say that Canon is my favorite. Besides its great performance and superb lenses, Canon's technical support is phenomenal.

Keep in mind, as you probably already know, the lens is more important than the camera and the mind of the photographer is the most important of all. I've known people who do consistently incredible work with iPhones and point and shoots and could probably excel using a home made contraption made of things they found around their homes.

Yes, I would find a way to show my work here as well as social media spots, a personal website, local venues and everywhere in between.

Much inspiration, satisfaction and gratification comes from sharing work with others and helping each other learn. None of us know everything.

www.ellenzaslawphotography.com

Definitely worth researching.

What I do know is to avoid condensation at all costs. Lots of silica gel bags.
Always remove your battery when done, and if the humidity is high you
should have a dehumidifier in the room that the camera will be stored in.

It's accurate and valuable, like a good x-ray is in your doc's office, but you get real good at eyeballing things after time.

The latest version of Photoshop CC at all times. Add a few plugins like by Alien Skin, On1, Luminar, Topaz, Anthropics... you'll be in the best candy store in town. If you're not too serious about it, Lightroom will probably do you.

Think Tank and Pelican. Like them better than the Low Pro I gave away.

Four Canon full framed sensors. Yes, I use them all.

I use a 16-35 on every shot, including bathrooms. Some of these rooms are very tiny.

https://www.ellenzaslawphotography.com/portfolio/G0000w8BozsWFkBs

Arca Swiss. I've had mine for 18 years. Wouldn't use anything else !

https://www.bhphotovideo.com/c/product/469923-REG/Arca_Swiss_801104_Monoball_Z1_sp_with.html/?c3api=3679%2Cbing%2C2763659969%2C4585581963538021

I put my 5 shots through HDR in RAW format and then edit them in Camera RAW. When they show the dynamic range but look natural, I'm done. IMO, the over-processed dramatic look tries too hard and is a kind of trickery attempting to be passed off as good photography. Drama and/or over-saturation does not fix a mediocre image. www.ellenzaslawphotography

Most of us are vexed because we know how generous their policies are. There really isn't any better place to shop.

No no no... If you returned it within the time period in its original condition and packing, and you bought it from them brand new, you will get a full refund and that's that. There is some confusion and it will be cleared up by them.

I've never had to pay the restocking fee, though it would be fair. Their customer service is positively exemplary. Get to the bottom of it and please let us know.

You really need to call someone "high up" in customer service. I've never heard anything like this before in the twenty years I've been buying there and I've sent a handful of things back, (within their time parameter). Most of the time they've even paid for the return back. If you don't get satisfaction, use the magic words... "Abes of Maine."