Questions about example sentences with, and the definition and usage of "Preferences"

A: preferences means what someone prefers

A: "Preferences differ from person to person. Personally, working for a big company is always a wise choice. There are a couple of reasons why I believe that."

I think "would" is not necessary here because you are saying this is something that is already true. I also think "assumed" sounds awkward, because it sounds like you no longer think this is true. I would use a word like "believe."

A: Hi! yes it’s grammatically correct. Here’s another way of saying it,
“Each person would have different preferences. Personally, I always think it's a good idea to work for a large corporation. There are a few reasons for my presumption.”

A: Preferences differ from person to person. personally, I think working for a big company is always a wise choice. There are a couple of reasons why I assume that.

A: Your sentences are correct, but this suggestion is more natural:

‎Preferences would differ from person to person. Personally, I think working for a big company is always a wise choice, for a couple of reasons.