just depends, some wanna get the item before shipping, i personally dont have a prob shipping simultaneously to anyone on BF that has a reasnoble number of posts (ie NOT 1 or 2) and have shipped a bunch of knives/cash to members all over the USA w/out any probs, none whatsoever.
that said, i personally am going to shy away from the people trading who want to get my stuff first, hey, this is all about trust, and when i ship i take as much risk as the other party. so, myself, from now on i will offer to ship simultaneously, w/a 3 day period to check out the product. i think this is fair for all involved. but, i'm sure i'll see something i want, and even though i have about 1200 posts, they'll want my knife first, and i'll ship if i want the other knife bad enough, but i wont like it, and will try other options to acquire the knife if i can. imho most wont ship prior to recp't because of fear of theft, or getting a knife that isnt as advertised, BUT when i ship first, i take the same risk imho, ya have to really trust for this to work, imho, and imho the great majority of BF memebers are trustworthy, i just wanna make things more equal, BOTH parties show a little trust. why should i take all the risk??
that said, i would swap w/most on the site w/out reservation, the bad apples get rooted out/booted out fast, and i have seen one member w/LEO experience personally help forumites who have been victimised by bad people recover $$/knives or at least help get the proper authorites involved, no names you know who ya are

)
but generally i like to ship at the same time w/a agreed upon time to examine the knife, and if either party is not happy, just simply return the knives to the original owner. easy enuff, but not always works, as some,really relativly few, have found out. be sure and agree what ya are getting/expecting, be honest in your evaluation (always better to undertsate condition a little vs overstate the condition imho) LNIB is like new in box, hasnt been sharpened/opened much/etc. i use 95-98% to describe a knife w/LIGHT use, cutting paper, mostly carried not used, etc.,
and i know its a worry the first few times, the first trade i made i swapped a spyderco starmate/MT mini SOCOM and $200 for a crawford kasper ti folder, was worried to death, but all went 110%.of course i shipped first that time........
my best suggestion: be scrupulously honest, ship when ya say, a day or so is no biggie, but dont say i'll ship mon and ship fri, not cool, check the other guy for bad posts on good/bad/ugly,and i like a short phone call just to make sure all agree on the major points.
try to treat others as you would like to be treated, do that and ya will have a lotta fun, and acquire some neat knives/stuff.
good luck, have fun,just my .02 worth
greg