7 days man. That's how long you should wait before requesting a reroll

I think the idea is something like 7 days? At least a few to give the winner a chance ... its a weekend, maybe they're the lucky type that actually gets to go out and do things instead of sitting in front of their PC ... like me :)

1 full week after the giveaway is over. if he doesnt respond then check his steam gifts profile, if he wasnt offline for 1 week then make a support ticket reporting him ( theres chance he might use the key and ignore the feedback ). if he was then simply request new winner after full week

For future reference you should probably read the FAQ, as it has the answer to this and many more things.

1 week.
If the planets are aligned, add 1, in case of a conjunction subtract 1arbitrary unit of nonesense.

Yes, the winner has 7 days to mark the gift received by the SG rules.

Read the FAQ

Seriously, nobody do this?

Can only agree to what others said.
Please read the FAQ!!!!!

Dear 789it789:

It's been 3 months since you joined our community here. It is high time to browse through guidelines and FAQ. Knowledge from these pages can and will save you many headaches and problems. The FAQ was written to help new users learn the ropes of the site. As the main purpose of the FAQ is to answer Frequently Asked Questions, you should find FAQ helpful.

Once again, in case you missed it, I strongly recommend that you read FAQ as this will answer many of your questions.