I wouldnt put anything in there, until the roof is done, and since you are going to need it for storage, make that roof your priority, so you have a nice dry safe place to put things to store. Once they start working, anything could happen, and debris will fall and anything in there will definitely be in their way.

If the garage roof is not leaking, you can temp store items in the garage while working on the main house, after done move everything out of the garage, and do what needs to be done as the roof goes and everything else that needs to be done to the garage structure.

Or rent a storage Pod put everything in there if contractors want to do the garage and home improvement at the same time instead of 2 phases.

GN, unfortunately, due to availability, the schedule is what it is. Are you saying normally roofers will want everything out?

It depends on the scope of work they will do and how bad the existing roof deck is. If they start tearing off damaged plywood, etc to replace sheeting, etc debris will be falling down and could cause damage to your stored items.

Talk to your contractor and ask him if you can leave stuff in the garage and if he is willing to do the job with stuff being there while work is in progress.

Most will make you sign a waiver that they are not responsible for anything left in the work area, or that the homeowner is responsible to remove everything from the work area.

This is not a place to look for an answer, like I said before, talk to your contractor.

Everything out because of the existing flat roof and not knowing if the roof framing will need to be replaced. Since the decking needs to be replaced, there is a good chance that some of the framing will need to be replaced as well.

If this was a gable roof with a ceiling and there was no reason to suspect framing damage, then it would be OK to use it for garden tool type storage. With enough room left over for roofers to shelter in case of a sudden thunderstorm.

Gotcha. Thanks all.