When to give an estimate??

[Jackie Boyd]

ok so I've heard some people say that they give the "seller" a quote on how much they will take for the property right away. But I've also heard others say they wait and get off the phone first and then figure out their estimate. I'm wondering if waiting and not giving them a number right away can lose their interest? Also what if you do give them a number right away and decide "oh crap that was to high"? I'm new to this so just trying to figure out the best strategy!