So a big issue with timers is how other people are going to feel about them, especially people you live with. I guess I'm assuming a reader who is making some decisions about how to conduct their life and possibly having to explain some things about their disability to roommates or family members.
If you use a conventional timer (which I guess regular people mostly use for cooking?) then it's confusing to people because you're obviously using it for things that don't have to do with cooking and sometimes it seems like you're not using it for anything at all. Also, it can be a problem because a lot of people find the sound of a timer going off to be really unpleasant and/or stressful and then it's an issue of being considerate to the people you live with.
Actually, even unconventional timers like TV shows and singing are things that you can have to explain. If your family is really fussy about your disability, they might get upset because they perceive watching TV or listening to music as a leisure activity and they think that you should be doing something constructive. Even if you are doing something constructive and you try to explain that TV and music are making it possible for you to do it, they might just think it's an excuse.
Something that I find frustrating is that even if people are not annoyed with me for watching TV a lot, they don't understand my relationship to TV. Sorry that just sounded ridiculous, but what I mean is that people think I'm just really into watching TV shows and I want to sit down and watch TV shows with them. To me structuring my time around watching TV, instead of structuring TV around what I want to get done, is a waste of time, energy, and episodes. It can be fun sometimes just like any waste of time and energy can be fun, but it's a completely different activity from my usual TV watching (TV as timer).
Even if I do sit down and watch TV with someone (which is fine as a leisure activity and sometimes I'm prepared to do leisure activities), I feel tense because I'm not used to just watching TV and doing nothing else, so I like to eat, play games, or be on the computer at the same time. Obviously some people don't like this much so I try to make my secondary activity be eating or drinking because it bothers people less. Also, if I get drunk enough, dealing with being drunk can be the secondary activity.
I guess it's kind of a stupid thing for me to take personally but it can be hard for me to know that other people perceive me as doing leisure activities all the time when I am literally working hard at something right then.
Also there's the fact that people are a bit less likely to put up with something that mildly inconveniences or annoys them if they think you're doing a leisure activity than if they think of it as an actual support that you need. Some disabled people might think it's good if singing in the shower helps a person take showers properly, because it doesn't come off as different from other people. But it is also hard if someone says it's annoying to hear you singing in the shower, and they don't understand that by saying that they are making it hard for you to take care of your hygiene which affects your quality of life.