better safe than sorry it's wiser to be cautious and careful than to be hasty or rash and so do something that you may later regret.

☞ Apparently the expression is quite recent in this form (mid 20th century); better be sure than sorry is recorded from the mid 19th century.

2012New Zealand Herald We were told to get the heck out. I was going to stay, but it's better to be safe than sorry.