I've worn progressives for 20 years. I started with the Verilux and it took me about 4-5 weeks to adjust. You can't go back and forth with single vision lenses or your eyes won't adjust to them. Once I got adjusted I couldn't be without them. I was fortunate to had a good optician because the PD and centers needs to be absolutely correct. I have tried other lesser expensive lenses but they never could get right so I got my money back. In recent years I'm have a harder time adjusting to new lenses. I don't know if it's because I have more astigmatism or if the younger optician just aren't well experience.