Ok, so here is my quick rant.
Could we please ask forum members for 2 things when selling spiders:
Firstly, measure the spider first before putting it up for sale (Preferably with a ruler or tape measure). Don't thumb suck if you are using "tollie tape" (Fangs' term, thanks.

). And if you have to, rather under estimate. If I was a buyer buying a 15cm spider and I arrived to collect a 18cm spider, I would leave much happier. If on the other hand I came to collect a 20cm spider, and I pick up a 16cm spider, I would not be quite as happy.
Then, secondly, when selling a spider as female/male, make sure its a female/male. There is no such thing as 90% sure its female or probably a female when it comes to selling spiders. Its either 100% male, 100% female or unsexed. I have seen way too many people buying 90% sure females only for them to turn into males down the line. Makes for a very bad reputation for the hobby where you can't trust anyone. As for sexing a spider, only an exuvium will do unless it is clearly sexed by a person, who knows what they are doing, in some other way. Eg. some pokies can be sexed via dorsal patterns if you know what you are doing, some Lampropelma can be ventrally sexed quite accurately. If it has been sexed, please state how it was sexed as well.
Ok, so maybe not quick, but that should do it for now.

Have a great week all, and happy selling.