With the choice of the right material and protection class, you are on the safe side, especially regarding the appearance of the outdoor luminaire. Almost more important, however, is what you don't see right away: the right connection. Power cables and co. must also be protected from the weather and laid in cable ducts. In addition, not every cable is intended for installation in the ground. So make sure you use the right material here, too.
After all, it has the most important job: it supplies the installed lights with the necessary power. The connection of the luminaires to the power grid must therefore also be waterproof, of course. This is the only way to protect yourself and your customers from short circuits and their undesirable side effects.
Recessed floor luminaires present special challenges in this respect. Very few like standing water. If you install in-ground spotlights, you should never do so in depressions or recesses. You also need to provide drainage underneath the recessed box. If the humidity is very high during installation, moisture may accumulate inside the fixture. Therefore, it is better to postpone the installation until the next dry day.