I also put sealant (homebrew) into my commuter tubes, and I guess it got rid of flats. I didn't have that many to begin with, decent suburban roads/bike lanes, wide schwalbe marathon tires with low pressures, etc.
But recently a 3-day slow leak developed into a half-day slow leak, and I needed a tire change, so I pulled everything off, and found I needed THREE patches! I guess two of the holes were sealed (well enough) by the sealant, but when I took the tubes out and inflated them without the tire to support, stuff got jostled and the holes became open?
BTW I put the sealant into tubes with 'non-removable' prestas. That locking nut doesn't want to remove, but get some pliers on it and that sumbich WILL unscrew all the way off. You have to be careful then and catch the core as it falls into the tube. Secure it in its place inside the tube with a binder clip or clothespin while you put sealant in, then push that core back up and screw the locking nut back on.