When I was a kid my dad rode a single speed to work, but it was only about 1km from home. When he moved he rode 8km to work on fairly hilly roads on a geared bike and I thought that was a pretty impressive achievement. When he retired and stopped riding for health reasons he gave me his hybrid and now I am doing short 3.5km rides to start with until I am fit enough to ride 8km to work (less hills than his ride I think).