It is expensive to maintain a license, to comply with everything that is required, and keep clients happy that like to call you at all hours and days of the week. 

What's the best advice for a first-time real estate investor?

I read the tax regs and read it to say that if the property was not maintained and went into disrepair and you had to replace the "deck" you had to depreciate.

Some choose to maintain.

Nothing in this section relieves either the landlord or the tenant from their obligations to maintain the dwelling as those obligations are set forth in Article 2 and Article 3 of Chapter 12 of Title 55.1.e.

For example, investors strictly looking for cash flow may not maintain the property at the same level as a long-term buy-and-hold investor hoping for some appreciation.Build a team you can trust. 

If a house is properly maintained and upgraded, it can stand for a long, long time.

This holds landlords accountable for maintaining their property.

The house is well maintained but there are always a few things to be done after the green card inspection but this process has been painfully slow (our inspection was Feb 2020 and we still haven't received a report).

Culture of the group - is it established & maintained?