Pool Light not sure but should I just get a new one from intheswim or replace bulb

I had some pool guy who changed the lights for me but it blew off after 4 months or so. When we moved it I believe the pool was there for over 18 years. It is a nice vinyl pool. We made a lot lot lot of modifications to flooring, etc etc... through the years but did not change the Pool light only. We did over a year ago but it just blew off after a short time. I think maybe the light itself is bad? I think it looks like a Hayward to me.... stainless steel. Should we just change the entire thing itself or keep spending bulbs which I think he even changed the gasket but maybe it does not work well anymore?

Changing light fixtures (what the bulb screws into) ranges from moderately hard to impossible. The wire from the fixture goes from the light niche all the way to a junction box located above the waterline. Often, the conduit is installed badly, and the fixture cord is stuck, making it nearly impossible to replace the fixture.

If the problem is water leaking into the fixture, that can probably be fixed by getting a new gasket and being really careful on the installation. If the problem is voltage, THAT fix has nothing to do with the fixture.

There are other options, but first you need to do some checking:

+ What is the voltage on your lamp, 12V or 120V?

+ Do you have a digital multimeter? Do you know how to use it?

Thanks so much for replying. I have something like this

http://www.intheswim.com/p/hayward-replacement-lights

this was already there when we moved into 8 years ago but it seems to be in good condition still. I bought a 500 watts from intheswim thinking it will work. It did. For 2-3 weeks only and not it stopped working. I am not sure if the main electrical is one giving the problem or the bulb. Someone said here that a 100 watt flood light from HD or Lowes worked as well for 20 yrs without any problems. It makes sense.. maybe I should have done that instead.