It has definitely been a gradual process, slowly adding a property or two to my portfolio each year, but eventually getting to the point where I am now, with a reasonably substantial portfolio (mostly in Cleveland, like yourself).

I prefer to keep good tenants with gradual rent increases.

If you would be able to go back 20 years in time and drive the Philly neighborhoods and observe the gradual change in certain neighborhoods and the factors that contributed to change in each area, you would have a good understanding of how the change has happened and why. 

The 3rd will gradually become the 15th, then they won't have money on the 1st because they just paid 15 days ago, and on it keeps rolling.

Try to find something that you can add value to through minimal renovation while you live in it and gradually raise rents.

Increase gradually (do a little bit each month) so that you don't have a large move-out situation and keep tabs on occupancy as they increase, sounds like you have room to raise them, that's great!

This trend will gradually increase over the next four years.

Our approach has been to constantly make iterative changes and gradually increase the rate.

@David M.Thanks for your helpful reply.I do have an LLC and I will start exclusively with wholesaling and will gradually branch out into flipping and eventually syndicating.

A middle ground is to buy a producing vineyard and gradually replant, graft or retrofit the underperforming blocks gradually.