Sealcoating protects a sound surface. It cannot repair a failed one, and applying it to pavement with structural problems is money spent hiding a condition your capital plan needs to see.
Alligator cracking means base failure
Interconnected cracking in a repeating pattern indicates the base has lost support. Sealer over alligatored pavement will crack through within one season. Those areas need removal and replacement, usually as isolated patches rather than full-lot work.
Standing water needs grade work first
If water sits for more than a day after rain, correct the drainage or the coating is being asked to do a job it cannot do.
Fresh asphalt needs to cure
New pavement needs a season of oxidation before it will accept a coating properly. Sealing too early traps oils and produces a soft, tracking surface.
Late-season temperatures
Below roughly 10°C and falling, the coating will not cure to spec. A contractor willing to spray in October is selling you next spring's failure.
The short version
If your lot is not a candidate this year, we will tell you and quote the repair that actually matters instead.