Postpaid coz ur line will always "active".

Even ur statement is on 16-jan (for usage from 17-dec to 16-jan), u can pay it by 15-feb (due date).

So u got about 30 days "buffer".

While prepaid, if today ur expiry date, by 1201 if u didnt topup/reload and buy new plan, u are "disconnected".
Go to sleep at 11pm then wake up next morning, u are "offline".
Without wifi, u cant even reload/topup.

that is grace period before number is terminated.

the point is "offline".

worst case scenario:
u sleep at 11pm, wake up morning and reply all whatsapp/email before go to car coz ur phone is connected to ur home wifi.
once u drive, then u want to open waze - bam! no data. and u cant reload online coz again, no data.
go kkmart/mynews to buy reload, but no cash (and they wont accept card payment for reload), so try to pay with ewallet - cannot coz no data.
end up go to petrol station with atm coz need to withdraw cash first to buy topup - atm there offline.
so need to go to ur card bank's branch for the atm.

so inconvenience