I put some new 1.5" slicks on my mountain bike commuter about 7 weeks ago, the tires I bought don't have any extra flat protection and my commute has a lot of glass and debris. I was having a heck of time with flats, getting at least 1 or 2 every week. About a week and a half ago I installed some some rhinodillo tire liners. So far, no flats with those. Obviously a week and half is not an adequate test period, but as soon as I installed them my confidence went up, they just seemed like they would work. The tubes are holding air like champs now. Reading reviews I notice many people say tire liners cause flats by the ends of them digging into the tube, I covered the ends with tape which seems like it might help (could find out later that I'm wrong) and I made sure to to take the time to seat the liner correctly in the tire. Also any difference in rolling resistance must be negligible as I haven't been able to decide whether I can even tell a difference or not. After these tires wear out I'll probably try running some puncture resistant tires without the liners and see how it goes, but the way things are going I won't hesitate to stick some liners in if I find myself patching tubes. Now the tire liners better do well by me after this good review I'm giving them on here!!