If you are talking about mailing off the saddle - or even if they are picking it up locally, I wouldn't do it without being paid in full. If you are offering a money back guarantee, then I would only refund the money when you get the saddle back in the condition you sent it but not refund the shipping in any case.
If they don't want to do that, they don't get the saddle - period. BTW, cash only, no checks - PayPal is fine. What I've done with PayPal is to have them either pay before they came to pick it up, or on my computer when they come to see it but before they leave with it.
I don't think I will ever sell a saddle online ever again! I was going to do an even trade on a saddle for another saddle and I was ready to ship it out but never heard back after trying to get a hold of the person several times via email with no response.
I ended up selling the saddle locally but I would only take cash in hand.
I agree with iridehorses , make sure you get the full amount first and if the saddle doesnt work out they can send it back and get their money back or make it clear that it is being sold as is , no refunds....
On the flip side of this , I had a wonderful woman that I dealt with on tacktrader who was selling an youth english saddle and she was such a pleasure to deal with and threw in many extras like stirrups and and a saddle cover : )
It can help to click on their public profile and then their feedback scores! A lot of people don't leave feedback though, it could be a new forum member or their first purchase. It helps but it's not a sure thing. If they have slot of good feedback though you could be pretty sure they're going to be honest.