When can I stop putting diaper rash cream at night? Does it only stop when they are potty trained?

I only apply as and when required especially at night. I find that its rather uncomfortable to apply the cream for my baby as the cream will be sticky too. Afterall, i will change the diaper quite regularly and air my baby's bottom so she seldom has rashes. So i actually stopped like 4months after usage. Then only apply when there is rashes again which seldom occurs.