Anything over 10 kilometres (on FLAT terrain) takes quite a lot of time AND effort. Can be done, but not EVERY day. It all depends how strong you are, how much time you have, how exhausting your days are (work, family, training, sleep...).

I have 11 km one way (22 km round trip), half through heavy city traffic, half open road, and while it is mostly fun, it is still around 40 minutes of energetic pedaling that, on some days, I choose to transform into 10 minutes of relaxed motorcycle riding.