My 10-year-old pees in the bed every now and then. Is this just a "I'm too lazy to get up and use the bathroom" issue or is this caused by stress?
So there is a mix of things that can be done and things that are going on.
Older children can sometimes bedwet through trauma that's happened to them, for which they will require some therapy to get over. The trauma may not visibly show itself in any other area of their day-to-day lives, however it'll be in their thought life. Also it could be many things not just the very dark stuff (SA, CSE etc) like being bullied at school, fear of school, friends betraying them at school, home life changes etc. etc etc etc.
See This link for an exposition of bedwetting in children with trauma.
The article also points out that 1% of children are still bedwetting at age 15; what percentage of that is primary enuresis (never stopped) or secondary (has stopped for a period of six months and restarted) due to things changing or trauma or something is not stated.
There are things that can be done in the case that it's not trauma related, like giving your child big drinks so tahat they learn better bladder control and of course the rewards system whenever they do have a dry night with no condemnation when they don't (as that can make it significantly more difficult to stop.)
I think some kids just have more difficulty. I have three brothers and one of them wasn't completely accident-free until he was thirteen. Another was dry by the age of seven. My son was about nine when he had his last "accident". All you can do is help your son manage his anxiety, and to understand that no child would willingly pee in his bed just to avoid the effort of getting up to use the toilet. You might ask him if he wants a waterproof sheet on his bed.
Some kids just don't realise it when they pee in their sleep. In addition to the plastic sheet, you could stop water intake about an hour or two before bedtime(only IF possible) and insist on a visit to the bathroom before tucking them in.
To find out if its anxiety talk to the child in the morning about possible causes by asking about dreams/nightmares they might have had in the night. Make the pre-bedtime rituals fun ones and maybe add a night light so that visiting the loo in the night is not a scary task.