I have a few new properties and am looking into buying more but want to know from people that have been doing this for 5, 10, 15,20 years how much on average they have spent on maintenance/capex each month or year. I ...

If thats the case I'd be grateful for any helpful links.What are the most important professionals I should keep in contact with for apartment maintenance?

They often lack the experience, know how and skills that are necessary for a professional transaction.

so I'm I totally crazy for wanting to do this without an experienced partner? 

Basically, you are experiencing what would be typical of an association with weak funding - special assessments.

Go to where cash buyers work....at the courthouse steps buying at foreclosure auctions.If you see a guy bid on and/or buy more than one property,they are or work for cash buyers with lots of investment cash or lines of credit.Walk up to them after the auction and compliment them on their property purchases and offer to bring them more just like it before they get to the auctions.Ask for their criteria (sizes,locations,ages,numbers of bedrooms,condition,etc).Promise to follow up with them ASAP with a property they might like to inspect and purchase.Go to every courthouse you can get to in a few hours driving and you could easily create a list of 30 to 40 real professional cash buyers who act fact and know what they're doing to be profitable in this business.

I am also experienced in photography and drone video/photography. 

Bigger Pockets is the best way to go when reaching out to experienced investors and getting deals done the right way.

I was wondering if any more experienced members would be willing to share their stories about flips gone wrong, mistakes a beginner might make during the rehab, and stories about problems they have overcome to reach success? 

I have an experienced property management in the area so these can be turnkey.