Not sure if this was meant for just clients or for everyone, but I'm replying anyway. LOL 
I prefer same day or right away (within two hours). 
The further in advance the time is booked, the longer I am holding that specific block of time aside for that specific Gent. Then if anyone else asks for that time, I have to turn them down. 
If the first Gent cancels, I feel like I have lost double the revenue. I haven't of course, but that's what it feels like. And I have bad feelings towards him for something that is not his fault.
Or what if I have to cancel? Then HE may have bad feelings towards me for wasting HIS time. 
Life happens to ALL of us. We can't always predict it. 
So I just choose to not run the risk of anyone feeling bad. 
Screen in advance, book same day or last minute. That's me.