We had a guest a few weeks ago light the fake wicks on THREE fake plastic candles. 

"Excess of normal wear and tear" is not "negligence"...Think negligence as unintentional damage caused by the tenant..things like: candles left burning, stove left on, cigarette on couch, kids stuffing a toy down a toilet, causing the water to back up, etc...That stated, your comment: "Additionally, the renters liability portion would also be another layer of protection between visitors and guests and the landlord.

I got started on this plan at 21 but it wasn't until I was 27ish and burning both ends of the candle for several years that I was able to completely quit my regular job(s) and devote myself full time to my real estate business. 

If the tenant is burning incense or scented candles or has sprayed air freshener just before inspection, it is a red flag.Even with all of this, a smoker sometimes gets through the net.

Do you permit tenants' use of candles of attempt to regulate their use?

Moreover, if the house smells of too many synthetic fragrances, like candles, air fresheners, or sprays, it may be to cover up problematic odors.Check for leaks under the sinks, basement, windows, and other areas if you notice a moldy odor.

I shouldn't have deleted the front door photo and the dining room.. there were more red splatter there, plus burnt candles.  

They are a little more expensive to work on, because everything is custom and hand made, plaster instead of drywall etc.

So for me , especially starting out, paying little bit more but having more cash in hand made sense.

Clotheslines, hammocks, outdoor showers, outdoor seating/eating spaces, and bug repelling torches/candles (preferably torches so they can't be moved to areas where they become fire hazards) are all good options for outdoor amenities.