my mare has cushings and until this year she has been clipped all year round for about 3/4 years! just need to keep an eye on the weather and put a light weight on if its going to rain as she was more likely to get cold!
My friend used to clip every 6-8 weeks as her mare had cushings. If they need it, clip them. People who intend to show their horses won't clip past a certain point in the year so the summer coat isn't spoilt. One of mine is currently out naked and as happy as larry. However, at some point in early March the whole lot will come off as he takes ages to shed (and has done for 22 years!) and I don't want him getting hot under all that hair.
I totally agree. A friend of mine got all manner of grief from numpties for clipping all year round, but the horse was working hard, had a dense coat and was getting very sweaty and uncomfortable. Much kinder to clip in those circumstances.
I clip all year round if the horse requires it. and after a week or so of fresh clipped'ness, the coat starts looking glossy and lovely again, as were he show jumpers i worked with who were clipped year round.
I'm actually yet to see a horse with a coat that has been 'ruined' by clipping after 1st of Jan as so many people profess to happen if you clip after that date