We started potty training our 3yr son 7 weeks ago (just after his birthday).
We started because his nursery tried taking him the potty a few times and he seemed fine with this. Also he seemed to be noticing when he was doing a poo.
Throughout the 7 weeks he has only asked twice to go to the potty / toilet. So really it has been up to us to proactively and regularly take him to see if he needs to go. If you ask him if he needs to go, he is adamant that he doesn't need to. However, if you do take him and give him some encouragement he is generally happy to do a wee.
He has never done a poo on the potty / toilet, and general waits until night time when he has a nappy on.
If you miss that critical window to take him to do a wee (which is quite easy to do with a 4 month baby in tow), he will generally have an accident. He doesn't really seem to notice when this has happened. On average he will have 2 to 3 accidents a day, but there are days he has none (probably because we have caught him in time).
We have tried incentives in the form of stickers when he goes to the toilet, but this didn't seem to help.
We have generally been as calm and supportive of him as we can, and try not to make a big deal of it when an accident happens. However, although it is disappointing and seems a backwards step, we are now wondering whether we should give up for now and try again in a couple of months time.