At what age can I use a newer UVB bulb on baby chameleon?

[happiness]

I've been using a near expired UVB bulb and I worry it's not enough.
When can I use the new bulb I bought on my 1-2month old babies?

 

[Gavinsons]

I used a new bulb the day I got my baby veiled.

 

[jannb]

I recommend around two to three months.

 

[happiness]

Thank you!