When I first bought my boat, my highest priority was to install a 'dripless' PYI unit, as the boat only had an 'old fashioned' packing gland.
But time constraints conspired against me and I was unable to get it done before bringing the boat home, so I settled for installing GFO packing in the 'old fashioned' packing gland.
This actually worked very well for 2 years, I was able to adjust the thing so it would drip maybe a teaspoon of water from a days cruise while underway and none at rest.
I caught the drips in a small bucket which I would empty every week or so if cruising. But I longed for the 'totally Dry bilge' that the packless advertised.
So after 2 years of using the GFO at the next haulout, I installed the dripless unit- I could pretty much get it to stop leaking most of the time, but would still have that teaspoon of water at the end of a day's cruise.
Then I read/heard some of the horror stories of the catastrophic disasters that can happen from the tearing of the bellows etc.
Fortunately, I had saved the 'old fashioned' system, so at the next haul-out I replaced the high tech 'dripless' packing unit with the low-tech gland - still using the formerly installed GFO packing(which is said to never wear out).
So, here I am today 8 years later with the same GFO packing - no adjustments now necessary.
No drips while at the dock, and when cruising the chore of dumping a 1/2 pint of water overboard every week or so is minor.
In my case I would have been happy to skip the 'dripless' exercise entirely.