I definitely had one of two 510 atty's slightly weaker than the other. And yeah, I used it heavily for two weeks. Not much of an improvement. It also went dead a lot faster (the third week) than the previous which was still working 60%ish for 5 weeks. I went back to the 5 week old, gave it a good alcohol rinse and compressed air to get it out/dry. Filled it up and it kicked almost good as new. I had never done any maintenance besides the occasionally blowing out for flavor changes.
I have been using that 510 atty since, and it is still working at about 75%. I started using it 10/28 and almost every day minus those 3 weeks with the other.
Try cleaning your old one and you might get some more performance out of it. The following always brings my atty's back after a cleaning:
1. Start with completely dry atomizer.
2. Fill fresh cart completely, and two drops on the atty.
3. Take one drag, it will produce no vapor.
4. Take off the cart (should be bone dry) refill and two more on the atty.
5. Take another drag. At this point it will either still be dry (one more drop on each), or gurgle.
6. Get it gurgling and keep hitting it. You want it at the verge of flooding.
After that you just keep smoking it until it isn't gurgling anymore, and the vapor production should be really kicking at that point. Takes a ton of
juice but it works every time for me, and seems to be the fastest way to get the capillary action of the cartridge+bridge+coil working again.
Hope this helps.