If I originally had a Blackberry Bold and then changed over to the Nexus 5, does it make sense to still have the "BlackBerry Connect Plus (2GB)" plan on my account (i.e., does the 2GB affect my Android phone's data usage)?
You still get 2gb which isn't really available at that price anymore
If you ever need / want to go back to your BlackBerry, having that provision on your sim means access to BIS is still provisioned on your account. Without it your old BlackBerry won't function correctly without you having to change your plan.
It has no impact on the way your Android uses data so keep it.
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