95% of the products I sell I have tested myself, and the rest have been tested by someone I trust - or they don't even make it onto the site.
One example is that I've been sitting on this
new 250cc CDI/Coil combo for about 2 weeks now and not putting it on the site because I couldn't test it myself and no one I knew had tested them.
I knew they worked and are better than the adjustable CDI + a coil that they replaced in my product lineup from the manufacturer's info, but that still doesn't mean I can honestly tell a customer that I personally know for a fact they are better.
It wasn't until I was able to farm one out to a regular customer who was happy with it that I put them on the site (just last night!) I've got a waiting list of 5 people who waited for months that wanted an adjustable 250cc CDI - I still wouldn't list it until I knew more about it.
I never want to be in the position of "Oops, I should have tested that more" and having an unhappy customer.