How long are gates used?

[ucfalum]

I am curious how long (in general) safety gates are effective. I am a first-time mom and have no clue. Thanks for any input.

[emmiem]

I have a 34 month old and still use my gates at the foot and top of the stairs. They are steep wooden stairs about 18 steps and the landing at the bottom is slate. Ouch! I don't want my little ones going up and down without me. They do know how to climb stairs but I don't want to take a chance on an accident.
Emmie