What kind of mirror?

[salide]

I need a mirror for my bike.
Can I get some opinions about putting one on my bike or on the helmet?
Pros. Cons. Brands.
Tks

[Insight Driver]

I need a mirror for my bike.
Can I get some opinions about putting one on my bike or on the helmet?
Pros. Cons. Brands.
Tks

handlebar mirror: pro, always on the bike. Con, you have blind spots and you have limited rear vision in the mirror.

Eyeglass mounted mirror: pro, light, always with you since you should always have glasses on to prevent eye injury anyway. You can swivel your head, hence you can scan behind you and eliminate blind spots. Con: it takes a while to get used to using it since you have to change the focus of your eyes. This is the mirror of choice for most serious bicyclists.