I try my best to accommodate buyers. Howver, if paying by personal check, it does take 10 business days for my (your) bank to be sure it is not a returned item. Often, I look for an 800 number of the bank to call them to verify if the check cleared. Half of the banks will tell you; the other half will only tell you if the funds are available, which means nothing if there is a stop on the check, or if other checks bring the balance down to below the amount of the check writtent to you.
I also try to verify money orders and bank checks, as they can be stopped in some instances. I have my items packages before the check arrives most of the time, but I have had instances where some jerk never sends the check at all, and then I have to relabel the box, or even rebox because the item doesn't sell, or, in the case of tubes, someone wants a different quantity.