Tenants lease is over on the 31st and they are to vacate. Called this morning and asked could they stay an additional 7 days. Do I charge them, do I write up a weekly rental agreement, what do I do?

You have the option to do either one. If you don't have anyone moving in during that time, I would just charge them 1/4 of their monthly rent. It's really up to you.

I wouldn't bother with a new lease, just tell them they can stay but you will pro-rate their rent. If you do have a new tenant coming in, you need to tell them they have to be out by a certain date to give you time to prepare for the next tenant.

A lot will depend on your previous relationship. If its been amicable and they have been good tenants, then be accommodating. If they have been a pain in the butt, then you might want to get everything in writing.

Tenants lease is over on the 31st and they are to vacate. Called this morning and asked could they stay an additional 7 days. Do I charge them, do I write up a weekly rental agreement, what do i do?
Well the tenants actually broke there lease and I agreed to do a buyout for two months they had 5 months remaining now they need 7 extra days to move

Well again, its up to you on whether to be acomodating. Definitely, you charge them a pro-rated rent. Whether you want to formalize it in writing you have to decide.