A reseal is just a simple maintenance treatment and will not restore your space to good as new condition as many believe. There is also no simple to follow maintenance plan for your space. You see, based on your specific conditions you may have areas that get more or less sunlight, spots subject to irrigation runoff, sprinklers, wind, freezing, salt buildup, heat, snow, foot traffic, etc. This creates uneven wear on your sealer, a weakening bond in some places, weakened molecular crosslinking in spots, uneven chemical and ultraviolet damage, and loss of adhesion in areas.
Now by having a contractor slap some more sealer over the top of everything do you really think that this restores your space to as new condition? Now what If I tell you that over the years many different contractors came through and applied various different brands of sealers one on top the other and given that the wear patterns aren't consistent you will have greatly varying sealer thickness throughout your space. Spots which received little wear over the years may now have many times the maximum allowable thickness of sealer caked on. This will not allow the slab to transmit water vapor through and may cause moisture buildup leading to coating failure. Once some areas flake off, it's only a matter of time before adjacent areas fail as well due to a breach in the integrity of the sealer-concrete bond region. Another under recognized point of failure is that perhaps the last contractor put a solvenated sealer on top of a water based one. Do you know the brand of sealer that was last used on your slab? We have techniques to make educated guesses, but you can be sure that the contractor isn't getting a laboratory test done to ensure compatibility. To sum up a long answer, there can be no warranty offered for re-seal given the fact that the material we are sealing over may very well flake off, taking our shiny new coating off with it.
Now that you see the many shortcomings of the cheap seal, re-seal cycle, you can understand why we at time urge customers to move towards a more sustainable coating involving lower maintenance and greater longevity. Unfortunately, this often involves sand blasting the existing acrylic sealer off and starting fresh.