Don't be sorry. Everyone is a bit different in learning and memory etc - my wife says I started out as a Neanderthal and am now getting to be an old Neanderthal with memory/mental problems.
However I did 35 years in the classroom, it takes a different mind set to keep working with new people who ask the same questions over each year. And often multiple people with the same question in each class period each year. Repeated questions are a fact of life in teaching. If you can't handle it you need to look into another line of work.
amfoto1 is one of our more knowledgeable members here on the UHH and as you noticed can do long detailed analysis of a subject. But he sometimes forgets he is exceptional and others have to repeat stuff to get it or make a decision.

Keep asking questions - it is one of the main ways we learn. Two of the more common little signs of "wisdom" put up by teachers in the Jr and Sr High Schools were I taught were:
There are no dumb questions, only dumb answers.
Ignorance is not a crime, but failing to do something about it should be.

In class I put up signs for my students that defined three words as used a lot in school:
Dumb - not very intelligent
Stupid - a way of acting, maybe because you are dumb, but maybe you are acting like you aren't intelligent
Ignorant - You don't know something. Everyone on this Earth is ignorant, it depends on the subject of the moment. And "Ignorant" is curable. We call that cure "learning".

You know what amfoto1, I'm so sorry I'm frustrating you with the same questions. Since my TBI 30 years ago, I can't understand or retain things as quickly or easily as I used to, and daily, it is getting increasingly worse. I can read and read, but things disappear or get all jumbled up in my head all the time. For example, I know exactly how I want to ask my questions, but they don't necessarily always come out as I intend them to. Obviously something wasn't "clicking" for me mentally, prompting me to ask the same question a different way. Sorry it's frustrating for you, but it's even more frustrating for me!

I wanted to start taking photos again because it allows me a small escape, I end up with something beautiful to look at that I can keep and look back on to remember, and I don't have to constantly think, think, think to try to sort something out inside my head...or at least I thought not, but maybe trying to start over, with a memory deficit, is a mistake on my part.

Before the TBI, I knew the computer and the camera inside and out; not digital, I learned on a Pentax K1000, and the darkroom was one of my favorite places to spend an afternoon.
Now, it's like a foreign language to me and it's VERY discouraging to sit and ask questions I know I already have the answers to, and can't even access them from my memory bank. I'm not trying to make excuses, it just is what it is. Simple as that.

That said, thanks for answering....again....but your snippy remarks really aren't any thing I need. I beat myself up enough without anybody else's help.

Before I leave, however, regarding those repetitive posts....without going into detail at the time, I very specifically ask for patience from the forum.

Regardless, I won't be asking any more questions. 😭

IMHO, neither one is anything to write home about (and I own an IS one, bought it years ago in a moment of newbie ignorance!). If you want some really good glass, try the 70-200, either the 2.8 or the 4.0. I have the 4.0 and it's a d^mned nice lens. The 70-200 lives on one of my cameras; the 55-250 lives in a drawer. Of course, the 55-250 is probably cheaper, certainly cheaper than the 70-200 f 2.8. And please don't talk to me about that extra 50 mm. If you need more reach, get the 70-300, I like it much better than the 55-250 anyway. I've personally never missed that 15 on the bottom but that 50 on top has to be worth something if you're worried about 50mm.

1. go to the canon usa refurbished site, they sell factory certified lenses with the same 1 year warranty as new in box.
2. The kit lens you got (18-55?) fits with the 55-250, but neither are high end, high image quality lenses. They are good but not great. Great costs $$$$ and Pro-Excellent costs $$$$$.
3. the 50 mm you are looking at is not much better but it is faster (in a lens "faster" means it will take images in lower light or at higher shutter speeds in good light) look below and see an f-stop/aperture chart. The bigger the number the smaller the opening and the less light gets to the sensor)
4. the "thread" has nothing to do with mounting on the camera, for your camera any lens with a Canon EF mount and those with an EF-S (has an extra part to prevent it mounting on a Canon full frame camera) Your body is not full frame, it has a smaller sensor called an APS-C and lenses made for it often have a rear element that projects out further-on a FF Canon it can hit the mirror and damage the lens and mirror. But the EF lenses made for FF bodies will fit on your camera and your sensor will only use the center of the image from the lens - usually the highest IQ area of the image circle.
5. the "thread" is the diameter of the screw threads on the front of the lens for mounting filters etc. one of my lenses uses 95 mm.
6. and none of those numbers has anything to do with how "far" a lenses will focus, most can focus out to infinity. there are exceptions, the closest focus distance though varies from lens to lens and lens type, macro (to nikon micro) lenses will focus so close that the subject is life size on the sensor. I have an old VHS Video camera in a box in the garage that focuses so close the front of the lens will hit the subject - I had it happen doing stop motion animation of a small diorama once.

One of the purposes of this site is to answer questions about photography. Don't apologize for asking.
f/stop is an aperture designation that indicates the amount of light that a lens allows to reach the sensor in the camera. The higher the number, the less light. The trade off is that lower aperture numbers, although allowing more light, produce less depth of field (DOF). That is the area of the photo that is in focus. For a landscape higher numbers are usually desirable to get as much in focus as possible. That's usually f/8 or higher. For a portrait where you want the person's face to stand out lower numbers are desirable. Lenses of different focal lengths can have the same aperture numbers. It's all in the design of the lens. Primes and some zoom lenses, usually higher priced, have constant aperture such as f/4 or f/2.8, or lower for primes. Many zooms have variable apertures, such as your 18-55 and 55-250. As you zoom out the maximum aperture decreases from f/4 to f/5.6. Understanding aperture can help you get better results with almost any photo.