One myth must be pointed out and that is - A grown cat is more difficult to rehome than a grown dog. A dog lives in a pack where the other members are his life, a cat lives in a home (the cats territory) and accepts you as part of his family. For the dog you are number one, for the cat you are a close second. It is much more traumatic to a dog to adjust to a new pack if he was happy in the old one. The cat will be nervous not to intrude on the territory, but as soon as the cat feels sure that he is welcome in the new home he will relax.
Cat or dog would adjust quicker if the new home is better than the previous one.
A grown cat will live a long life with you. The record age for a cat is more than 32 yearsThe adjustment is from your side, not from the cat. As we pride ourselves with being more intelligent than the cat, that should be easy enough to let the cat show the way
First get the cat to like you and give yourself time to know the cat's preferences.
Luxury will be appreciated, but not always prefered.
One deffinite advantage of a grown cat is that he can be left alone when you are out working. The cat will enjoy to sleep. Some cats are real loners, while others would want some company.
Get some back ground if possible. If the cat is a rescue cat then you can opt for leaving him alone, or if it was obvious that the cat had a friend in the rescue center, take that cat as well. Double the joy.
Cats can be friends with any other pet and that includes humans. There is no need to keep two cats if it is not practical, but if you do not have the time to spend playing with your cat then it is kinder to get him a friend, any friend.
Remeber if the cat likes the new home, he will welcome you to stay there too