When to Sell a Property?

[Sandra Holt]

I have two properties (soon to be three on Friday, woo hoo!).  My first rental was initially my primary home, and I moved out 6 years ago and it's been a rental ever since.  I'm thinking of selling it but want to know what others' thoughts are on when to sell a rental.  A little background about this particular one:  

It's on a 15 year mortgage and I squeak about $50 per month net on it.  Cash flow is not a problem for me since my husband and I have high paying jobs.  

It will be paid off in 10 years, then my net cash flow will be about $1,500 per month on it.  

I have about $120K equity in it currently.

I think the neighborhood is in decline since I've moved but that just might be my biased perception since I live in a nicer area now.  Maybe it was always a little rough around the edges and I just never noticed...

If I sell, I would like to do an exchange to buy something nicer/bigger, maybe even a commercial property (although I have a lot to learn before I buy a commercial property).

Anyway, if people could chime in as to the criteria they use when deciding to sell a property, I'd appreciate it!  I just don't want to hold on to something for too long if the equity in it could be working for me although the idea of a paid of property that cash flows nicely is appealing also.  Thanks!