Catholics: Regarding Purgatory, and not a "bait-&-bash" question -- can you stop praying (read on) . .?

I don't want to be presumptuous and think somebody is out of purgatory when they aren't, so I keep praying for them. Although there have been times when I think, "Whoops -- haven't prayed for Aunt Anne for a while!" and then I start up again. I just ask the Holy Spirit to keep prompting me to pray for the souls who need prayer.