Some yarns are indefinitely froggable, and others are more delicate. I haven't used mohair, and I'm sure different brands are different. So treat it gently; and I do know that you should roll mohair up right away unless you want a blob of knots. You can tell by looking at it if its getting frayed. Yarn doesn't get all stretched out or anything from knitting and frogging with it. I think it's more the friction that can damage it. If it looks in tact, you should be ok.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry