Just a few lessons I've learned in the past with dealings:
1. Although it acts like a locker, it may not be. A battery impact and an oil pan can check that in about 2-3 minutes. The oil will tell you more than anything anyways. Look for silvery metal chips. Save the oil though, take it home and let it sit and then pour off the best portion off the top if it is clear enough to re-use.
2. Simply never buy/sell a used axle without the cover removed anyways. It's just proto-call for nobody has X-ray vision. Items wear even sitting still in your shop without you knowing. Or unless you just had it serviced at ECGS.
3. Same goes if you are selling chromos. Unless you have receipts / pictures, pull them before selling an axle. Or give a money back warranty of some kind.
4. If someone gets butt hurt for you testing / inspecting, simply offer a price on the spot that you can live with "As-Is" to take it and go on. Or simply just go on.
5. I work hard for my money, I will make sure it is spent well no matter how long it takes / pains needed. Prepare by taking the tools you need to inspect with. If ever called names, return the favor.
What's to hide when you are selling something??? The guilty dog usually barks first!
6. A "word" is never just a "word" from someone you are not acquainted with and especially don't live close to without references or a warranty. Could be just a "word" they were told and only relaying.
7. Never travel somewhere and buy for someone else unless you send plenty of pictures for a confirmation before dragging it home. What looks good to you may not for others. I did this one time and never again.
8. Buying used "fab-work" 8 times out of 10 can / and most likely will bite you in the ass in the long run unless the fabricator is well known and experienced. Fabrication skills should never be taken lightly when your life / personal protection is at risk. A tire carrier / or roof rack sure. A cage, NOT! A few more dollars up front can most likely save you money in the long run on a cage / chassis. And re-sale value is more too.
9. You can only blame yourself after you shake hands and leave with something that is not what you had expected when you get home. A deal is a deal regardless of the stink you create afterwards. Unless it has some sort of warranty.
10. After you sell something to someone, they have full right to do whatever they want to with it. It's NO LONGER YOURS!!! I'm guilty of this one (once) myself. Sorry again Doc!
11. If you are un-knowledged about the item you are looking at to purchase, pay someone else who IS to go look at it with / for you.
12. It helps to buy from a closer knit forum such as NC4x4 but it still ain't 100%.
13. If you plan on further sales by means of the source you are selling from (CL / NC4x4 / etc.), Simply man up and present at least a 2 week money back guarantee from day of sales. I guarantee everything that leaves my premises for at least 2 weeks. If you can sell / do it once, you can sell / do it again...
14. Know what you are selling or be up front on an "As-Is" basis and price if you can't prove it. Anything is inspect-able / besides inside of a sealed tube (see #8 above).
15. Always consider forgiving. Never consider forgetting!!! Once bitten twice shy. But save some from the end of your life-span for excessive worrying and simply lick your wounds and move on. I towed a vehicle for my 3 door down neighbor from downtown Winston Salem to Durham and never even got a pat on the back. He had the nerve to call me again needing another tow not too soon after.
You can only hope with time / what comes around will travel back around. But don't be stupid and try to get back in any evil way. Karma works both directions...
16. "Assume" is just that... "Ass U Me"...