10 is awfully young to have arthritis. If your worried about negotiating $500 price difference I would pass on this horse. The maintenance is expensive! Supplements, joint injections, x-rays, bute, magnetic devices, led light blankets... The list goes on. Then when she is to arthritic to be ridden? She will still need somewhere to live, food, shoes, supps, meds, etc. Then will you be able to afford another while paying for the maintenance of this one?
A horse with visible arthritic changes this young is probably going to be a money pit! If you dead set I would get set if xrays on not only the joints that are effected but on the ones that aren't as well.
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