I did finasteride and rogaine together for a while after using only rogaine for years. About 6 months into using both, I actually started growing back in some hair I had lost. Doctor told me that almost everyone would hold their own using both and that about half would see some new growth. I then asked him why he had a huge bald spot. He said "I would never use finasteride; that shit has a small chance of making your dick stop working and any damage is irreversible. Here are some citations for peer-reviewed articles." I went home and read the articles--then threw the finasteride in the trash.
Still use rogaine (actually the Kirkland brand) twice daily and it is no trouble. I wish I could have stayed on both treatments and I feel I am only slowing the inevitable now, but I can't bring myself to shave it all off because 1). I have a hot young wife; 2). I have three places on my head where I had to get stitched back up and I suspect I will look like Frankenstein if I go hairless.
But seriously, read up on the finasteride. The risk is small--but it scared me.