Vacant 4-plex Rehab Strategy - Rehab all at once or one at a time?

[Mike Hsiao]

I have an offer in on 4-plex property that is currently completely vacant. It is 2 stories.   Top story has a 2BR/2BA and a Studio. Bottom floor has a 2BR/2BA and 1BR/1BA 

The property will need full rehab of all units, including plumbing and possibly some electrical work.   Principal and Interest per month would run about $8700.  My GC estimated about 60-90 days to rehab the entire property.

So I asked my GC about the idea of rehabbing one unit at a time  very quickly starting with the 2BR/2BA upstairs unit to get tenants into that one quickly for income. Rehab the next 2BR/2BA, get them in quickly, etc etc

My GC said it's better to rehab all 4 at the same time and just get tenants in when they are all finished.

I can totally see why doing them in series would be more of a pain for my GC, and more of a headache to schedule his sub-contractors in for each unit.  But i can see if he planned it out right, it can be done effectively.

OR if it truly would be better to just let him finish all 4 units first, then just get all the tenants in at once.

Just wanted to get the thoughts of people here to see if it's really that big of a headache for the GC and he is just wanting to make it easier for himself?