A freshly painted pool deck looks great for a season. Whether it still looks good in three years depends almost entirely on what happened before the first coat went down.
Most coating failures start with a dirty or weak surface. Pool decks collect sunscreen, algae, mildew, and old coating that's already letting go. If the new coat goes over that, it bonds to the dirt instead of the concrete, and it peels. Proper pressure washing and removing loose coating is the most important part of the job.
Cracks and low spots need to be repaired before coating too. Water that sits in a low spot or gets into a crack works its way under the coating and lifts it, especially after a summer of daily storms.
Finally, the product matters. Pool decks need coatings made for wet, sunny, barefoot areas, applied in the right number of coats with enough drying time between them. Skip any of these steps and you'll be recoating again much sooner than you should.