I've got the common sense items such as clean the lint trap, report leaks ect.

You have 2 tanks, 1 above the other, with a water wheel (alternator/generator) in the middle. 

Wholesaler had it for $90k "as-is", another wholesaler bought it, cleaned it out, and relisted it for $120k.

This person will most likely always pay on time and their is a higher likelihood they are clean which will mean in the end of their lease you can lease it to the next person while theyvare there and the deposit will cover the small charges. 

Purchase price: $420,000 Cash invested: $15,000 This buy-and-hold property generates a steady cash flow, with a gross monthly rent of $3,900.

One of my friends uses comped quarterly cleaning as their inspection day and trains the cleaners to take photos and videos of everything.

Analyze potential rental income versus expenses carefully to ensure the property will generate income from the start.

I would add that you can go a long way just having some clean color schemes (two wall colors and one trim color will do almost any house) and a few tasteful accent pieces. 

We have a few of these (not this brand but they are all the same IMHO) and they will help keep the sofas clean$89.90 - uhome 8.5qt Stand Mixer - https://www.walmart.com/ip/uhomepro-8-5QT-Stand-Mixer-Home-C...This is intriguing to me.

If I did my math correctly, on a 3,600 SF triplex where you buy the land for $150k, you generate a gross profit of about $84k (based on a $140/sf build cost and sale price of $205/sf), before you pay interest on any borrowed funds or closing/commission costs.