I use it as a deterrent to lead the tenant to paying on time.

They have the visual in their mind of a place that needs work, and that is the image they tend to keep - that they are living in a unit that needs work, so they will find work for you to do, in my experience.  

The best deterrent for squatters is an occupied house so I would suggest getting it back on the market and rented quickly.  

You must clearly spell out or paint a visual picture of what will likely happen if the tenant ignores your memo.

Hmmm well I don't have a lot of personal experience with this, but my initial opinion is that it's basically a deterrent to having pets on the property - in which case, if you are trying to discourage tenants with pets, just don't allow them. 

My position is that I don't discriminate and your no smoking policy is a great deterrent.

The late fee is a deterrent not a way to make money.

I enjoy large, longterm projects where I can visualize big picture scenarios and execute.

It is hard for almost all of us to look past the visual.

Prior to the walk-through, be sure to set expectations for you having the visual access you need.