An hour before light. At least.

I like to get in at about an hour before sunrise. Gives me time to get set up and comfortable before legal hunting times.

I try to get in my stand at least 30 minutes before first light. I'm not talking sunrise here, I'm talking 30 minutes before I can see from my stand. The earlier you get in there the more time things have to settle down and the more time your scent has to disperse from where you walked in. JMO

I try to get in 30 minutes early but the weather has a lot to do with that. If it's too cold I know that extra 30 minutes in the front half of my hunt will knock about an hour off of the end of my hunt. I guess I'd rather be early then too late!

I try to get in and settled at least an hour before sun up.

After reading some of the stories about the poachers, they get into the woods two to three hours AFTER dark.