It sounds like two problems. The first is probably you aren't thoroughly priming your cartos. I also use the condom method.
The second is your punching is probably damaging the carto and causing excessive o-ring wear. To confirm that, get some laser-punched or laser-slotted and try those awhile. You may also be damaging the o-rings in normal use. They should last a very long time.
It's best to use a tank tool to keep the sharp drip tip end of the carto from damaging the o-rings, but you can get by without one with an unflanged carto by using the following:
1. Always insert a carto into a tank end cap with the connector end first and a little juice on the carto to lube it. Never the sharp drip tip end first.
2. To refill, push the connector down into the tank, leverage it over to the side with the drip tip and fill from that end. That way what you're pushing past the o-ring when done isn't the sharp drip tip end of the carto.
3. To replace a dead carto, even in a full tank, place the connector of the new, thoroughly primed carto in the drip tip end of the old carto and push the new carto down just past the first inner o-ring. Flip the tank over and push the new carto up into the tank until the old one pops out the top and the new one goes past the second inner o-ring. Blow any excess juice out of the new carto and wipe its connector off just as you'd do after condom filling, before installing on the mod.
Hope this helps.