Is this a fairly common occurrence?

This is the most common oversight by self-managers, but it's the one that could be financially catastrophic.

I am considering evict my tenant with at fault just cause due to the lease violation ( parking, trash, common area cleanliness).

@Albert Johnson We evict one or two people a year in Arizona for various reasons, the most common being non-payment.

A common mistake I observe are investors focused on unit count rather than the fundamentals of the underlying real estate that's being bought.

Is this common practice or does it at least seem possible?

This Is a common concern for people doing a 1031 exchange.

There are many tax strategies.Structuring operations with a holdings and management company is a common strategy among real estate investors.

You use the funds of others to fund the deal, you do the work with rehabbing, renting, and managing side of the deal and both you and the initial investor whom invested their funds split the profits 50/50.This is one common way it is done for fix and flip.

@Nubia SilvaFirst thing you need to look at is your condoDocuments and understand what is common area vs unitFor example a plumbing line that is a main that runs through the walls may be considered common area but if water is leaking around the drain in your unit then it could be your issue.First identify the leak which the condo association should be involved in when it’s unit to unit leak to get it reviewed to check where leak is from.