Does un-used data roll over?

[Milk]

Wondering if I upgrade my plan to the $40 4G with 15gb data ------------------Would the un-used data roll over to the next month or would it be lost?

[dabr]

@Milk    I notice that you've been a community member since 2018, so you probably are already aware that plan data never rolls over?  

If you've never changed plans before and are wondering about gifted or purchased add-on data or mins, then no need to worry as plan changes doesn't affect those.  The only one thing that might be affected is activation bonus data which probably doesn't apply here either.

[HALIMACS]

@Milk 

Plan data does not roll over.

Only added data rolls over. Such as with add-ons or bonus data.