Depends on the rim and how new the tire is. My tire levers are plastic, don't weight much, won't scratch my rims and for me make it a little easier. Most tires I can mount pretty easily by hand. The guy I helped the other day had Bontrager rims, don't remember the tire brand, and were pretty tight as they finally seated. I used one lever to pop them on. I could have done it without, but why ????

My fixie and my Competition both have old straight walled Weinemann concave rims with wire bead tires. Not fun by hand.