Deer wise up pretty fast. Stroll across a bucks bedding are and he won't use it again for a long time. Let him spot or sniff you on stand and you can forget about that spot for a week or two. But some deer are more forgiving than others, farmland deer in particular are used to people. Some of them will only be spooked for a day while others will go on with what they were doing just moments after you leave.
Now those truelly smart deer that grow big and live long only do so after about 4 seasons. I've seen the same young deer year after year get away with stupid acts only because I wanted to give him another year to grow a bettter set of antlers. At 4 or 5 years when he's got a decent rack on him, bam, he's a ghost. The most I'll see of him after that is a quick distant glance at a great deer as he quietly gets away without giving me a shot. I can think of 2 specific deer like that but one in particular. As a spike he was a comedian, for two years after that he was reckless, by his 4th he was good but by his 5th year this deer was an expert at evasion.