How reliable are condoms alone when used correctly?

So I know that condoms are only like 99% effective per year when used perfectly - no rips, tears etc. and will be put on before any sexual things so no chance of a precum caused pregnancy.

But I want to know from a ‘real life’ source - how reliable are they? Has anyone been using them for a long amount of time and if so have you had any problems? I’m new to sex and don’t want to get on the birth control pill at the moment, and I was wondering if I should wait or if I’m still okay to use the condom method (I won’t have sex on my fertile window if that makes a difference.)