First Time Investor: What could I be missing about this condo?

[Zachary Parrish]

What are some common things to look out for when purchasing a condo, especially noting I'm a first time investor?

I am soon to be afforded an opportunity to purchase 1 or 2 off-market condos in a prime location in a really hot vacation rental market. They're being sold because the owners (who are family friends) only travel to the location once or twice a year, and economically that doesn't make sense for them anymore when considering what they pay for HOA fees (they don't rent it out, only tenants are the owners, us, and our parents).

I personally have stayed in both of these condos, although it's been a decade since I was last in one of them. One is recently updated, and the other will require some updating. As far as I'm aware, the one requiring updating has no structural issues. The updated one is in great shape. 

I've checked Airbnb's in the same building, and all the numbers seem to work out from my calculations under conservative assumptions.

Things of note: 
- I'm unaware of the quality of the HOA in their duties
- The building is older, although is seems structurally ok from the outside

- I'll likely be able to acquire these off-market for under market price

- I'm a total noob, so I expect I'm not considering the whole situation