The mistake we see most often here is replacing a failed lock with the same lock. It feels like the cheap decision and it is the expensive one, because the replacement is already on the same three-year path as the original. On any door with a sea aspect the sensible purchase is hardware built for the exposure: sealed mechanisms, coated or stainless components, and fixings that will not bleed rust down a painted door within a season.
The same logic applies with more force outdoors. Padlocks on promenade gates, bin stores and roof access are fully exposed and unprotected by any overhang, and ordinary ones can be finished in a single winter. Marine-grade padlocks cost meaningfully more and remove a recurring expense that most bodies corporate have simply come to treat as normal.
Where a ground-floor unit opens toward the promenade, corrosion resistance and attack resistance are both needed, and that combination is worth specifying deliberately rather than hoping one lock does both. Genuine high security locks rated for coastal service exist, and on those particular doors they are the right answer. Higher up the building, where the only route is a monitored entrance and a lift, reliability matters more than resistance.