Quoted from McCune:Cliffys are great for a worn pf but not for a non worn pf !
I disagree; a Cliffy will keep the playfield from getting damage. He only makes the protectors for areas that are highly likely to get damaged. If you have a playfield that is not damaged in an area that Cliffy makes a protector for, you just don't have that many games on the playfield. It will get worn over time, why not prevent the damage instead of repairing it later?
Some examples are your ramps like the wall on Rollergames or the center ramp on Police Force. These ramps are usually around $125 if they are available at all. If you do not put a Cliffy on the wall shot on RG, it WILL get broken and the ramps are nearly extinct. Same thing applies to the center PF ramp. With no protector, it WILL get broken and they cost over $100.
The switch slot protectors are the same as the ramps. If you have a ball dropping onto the playfield in the same place over and over it WILL cause damage after a while. Why not prevent the damage? It does not have to be a Cliffy. Mylar is installed on there for that reason, the prevent wear in certain areas. Mylar is not going to protect a ramp from getting cracked though.
IMO if there is a protector, you are on the path to have a damaged field, just need to play more games. If you do not install a protector, why wax the playfield? That protects. Why clean the playfield and replace the balls? They are going to do the same damage. It is preventative maintenance, DO IT.