This is my 3rd pair of Tifosi Slips and only replaced because I lost the others.  I wear them for everyday as well as cycling.  The one piece interchangeable lenses are better than the two piece designs.  I've owned a couple of pairs of Smith Sliders, at about 2x the price, with individual lenses.  The Tifosi frames fit snugly, and you can customize the temple length by simply bending the tip to curve around you ear.  The frames are flexible so that if I put my helmet on first and forgot to put on my glasses, I can still get them on over my helmet (to avoid losing any more Tifosis, I've added a neck strap). Follow the instructions for changing the lenses, and do not snap in the bridge before securing the outer edges of the lens. Note that if you have an older pair of Slips, and think you can interchange the old lenses with a new pair, you might be surprised to discover that the bridge "notch" on the lenses is different. You can order clear lenses from Tifosi if they don't come with your set.  Tifosi customer service is excellent.