That's a hard question..there is a ton of variables to consider...
On a well placed lung shot pass thru..on a morning hunt i will usually wait 30 minutes...than i will get down ..get my arrow[first important piece]...and if its covered in good red blood and everything else dictates a good shot im on it and ready to retrieve my deer..
Mind you thats when all looks good ...the reaction of the deer [the famed mule kick]..the follow thru indicates the arrow blasted thru with good blood and no fading light...thats ''my'' time line...
Now i have taken blood trails as early as 10-15 minutes before: here's one example: At a state park.. i hunted a mid December snowstorm...[actually right before it started]... and wacked a nice ten point buck chasing a doe...the snow was knee high and the shot was great but without a complete pass thru the blood trail was light...and the snow was coming down hard with big flakes. covering up good sign......i waited 8-10minutes and got down...i followed the blood and hoof tracks in the snow...40yds away the big buck was bedded under some pines and couldn't get up.....though he tried...the arrow lunged him and smashed the opposite front leg/shoulder area...breaking that leg ..i drew back my bow..[arrow had already been knocked]...and his head flopped down dead before i shot...i don't regret the move to get on that trail when i did...the snow as coming down so hard by the time i pulled next to the trail with my truck...the tracks were completely covered and so was my buck....my truck was an old Ford f-150 with a 3 inch body lift and 33inch tires ....i hoisted the buck on the hitch hauler and headed for the local Casey's store...for coffee...i drove back thru the park before heading home and you couldnt see my drag marks ...my footprints or even the trucks tire marks!!!...did i mention it was Snowing?-
One more bit is of course marginal shots..more time is always warranted... you will hear various time-lines. from experienced hunters...i rarely will let a deer go over night...actually it's a last case scenario in my book...either because of a gut -shot..or other circumstances....coyotes are prevelant in my state of Illinois..and a deer left overnight might just be a carcass by morning.
I hope this might help a little bit...on a good shot i only wait 30 minutes and get down and get my arrow ..if something dicates to wait longer i will....gut shot gets a minumum of 8hours or overnite...thats just my op.Jon~