We did it with DS. We started at 2 hours per day for about 6 months, then got told we could stop so didn't wear one for a while, then changed consultant and went back to patching 6 hours per day! (Not sure if first consultant made a mistake, or if DS just happened to deteriorate a lot in that time).
He made a big improvement with the patching, and we went back to 3 hours per day to maintain it, then dropped to 2 hours. We were reviewed every 4 months. DS's glasses prescription changed at least once a year too, but you can get a voucher to pay for them from the NHS. We pay extra to have the lenses thinned etc.
DS started patching aged 3, restarted aged around 5 and stopped wearing them at aged 7. There was a rapid and large improvement at aged 5, then it stayed about the same for probably a year or so.
Our new consultant wanted DS to continue wearing the patch even though it wasn't actually making an improvement, so that he didn't go backwards. I don't know if this is standard practice, or because DS had gone backwards in the past.
DS was slightly allergic to the sticky patches, so we bought cloth patches from meyepatch (you would have to wait until you had glasses to get them if you did this, because they fit in different ways depending on the type of frame)
He still wears glasses, a year on from stopping the patching and probably always will.