I just recently added a triplex to my portfolio which is going to be a BRRRR...down on the Jersey shore, and it’s going to need a 100% renovation, from top to bottom.

You could do a reno to your unit as extensive as a full remodel, or just a roof, HVAC system, and/or upgraded electrical service (you get to add it to the reno because it affects your 1 unit but it is great because that infrastructure improvement benefits the other units incidentally).

It’s also a good opportunity to install storm-proof amenities (windows, doors, roof, etc.), which raises the value/rent.

Question I have is about roof age and AC and if I should change it or sell as is?

What you are going to need to do is spend some time on the phone calling local Banks and Credit Unions. 

You are probably going to need to do individual property analysis, I don't think there's a good rule of thumb here.6.

The first contractor I ever hired was for roofing.

Landlord remains responsible for major systems (heating, A/C, roof) and replacement of appliances if one is not worth repairing.

I guess the gold nugget is to find a 0.75% property in a neighborhood that has low taxes and that has most of the CapEx (roof, heater, AC) recently replace and hope your tenant stay for at least 2 years (that's why I'm so focused on good school districts). 

Outright lies about a leaky roof, etc.