Do you always do a pre-purchase exam before buying a horse?? On 2 out of my 3 horses, yes - the one I didn't was essentially a freebie, and I couldn't see anything wrong in the 2 week trial I had her for, so I didn't. Should I have? Yes - even though nothing has cropped up, I still feel uneasy about not getting it done. I STRONGLY suggest you get a pre-purchase exam on ANY horse that you might buy.
Do you do just the basic exam or x-rays nose to tail?? I just get the basic exam. Having said that, I SHOULD have gotten full X-rays on my Grand Prix prospect, because he ended up not being entirely sound, which didn't show up with the basic flexion tests.
If you aren't planning on doing any upper level work, don't bother with the x-rays, just get the basic exam - a horse should pass a basic exam, or you should walk away.
Anyways, if you feel the need or want to get X-rays, then do! It is more expensive, but could be better in the long run.
Do you bring the seller along? The seller is usually present, yes. They can handle the horse for the vet if you don't feel comfortable. However, some people don't want the sellers to be present, so you can request that as well. I wasn't present when my mare got her pre-purchase exam when I sold her, and it turned out well.
I would recommend getting your own vet to do the pre-purchase exam, instead of using the seller's vet. Although vets are supposed to be neutral on the horse... they are people, and can be bought out by the seller.
Any other questions?