I’ll just steal the example from the page I linked:
夏休みになると、母の実家によく行ったもんだ。
夏休みになれば、母の実家によく行ったもんだ。
This is something the speaker used to do often during summer vacation - not just once.
(There is a separate grammar point for how もの is used in this sentence to express something that used to happen in the past.)
It’s not strictly necessary to use a conditional - e.g. the たものだ grammar point’s examples just use 夏休みは etc.
In general terms, when both ば and と can be used, the nuance difference is that ば focuses on the condition (and how to make it true) while と focuses on the result.