I have two sharers for my sisters cob. (he lives with me 24/7, my sister lives in Cardiff at uni)
I have one sharer who pays £50 every month. She can ride as many times a week as she wants and has every saturday. But generally she only rides a maximum of twice a week due to work commitments. But she helps massively in the winter with poo picking on a saturday and filling up a zillion hay nets for the week! She will also go up and feed/hay when i am away.
The other sharer is a friend of a friend and pays me £10 every time she rides (her day is a sunday), but if she doesnt ride she doesnt pay. She doesnt have any responsibilities, i don't ask her to do anything, just to feed Major and my girls sometimes if i am away. She is a teacher and in holidays/half terms she goes away in her motorhome, so it means he can be free during holidays for my sister to come up to ride and take to fun rides.
obviously in a good month i would get £90 per month off my sharers which covers his rent. My mum pays everything else for him whilst my sister is in uni.
Personally i think £50 that i charge my part sharer is peanuts compared to what other sharers pay....but i want to keep her, she's great and she couldn't afford more. What is the going rate for sharers in your area? If your not after the money then i would aim for a token amount like £50 - which is a good deal for both them and you. I would be honest from the start and say its a flexible part loan so therefore in lieu of them having no responsibilities then you may occasionally need to take the horse hunting/competing etc. I have been honest from the start with my sharers and they have no problems when my sister comes up to visit and Major isn't available for them
I love the sharers i have, the roles work out perfectly for everyone involved i think. A friend of theirs also rides moet on a saturday which is great but i don't ask any money as its doing me a favour when i am playing hockey!