I've been wearing blue light glasses for some time now, mainly because I spend the majority of my time in front of a screen.
Personally, I limit wearing these glasses during the day and try to work with the natural light outside.
Once the sun goes down, it's time to get them on. Why? Because our circadian rhythm is heavily dictated by the cycle of light and dark.
This means that wearing them in the later hours of the day helps you to wind down for a good night's sleep.
In the summertime, you may like to have them on before the sun goes down as the days are much longer. Especially if you're someone that makes it into bed early.
The absolute essential time for me is when I'm using a screen in the evening, whether that be working, editing, browsing, or watching.
Screens shed an enormous amount of harsh light into your eyes which keeps your mind wired in.
If I'm ever editing and have to take them off (as they have a mild yellow tint which affects the colors you see) I always struggle to wind down and go to sleep.
I also use software called "flux" on my computer and turn my phone into "night shift" to further reduce my exposure.
Finally, this is not exclusively about screens - having your "main" lights on in the house should also align with sunlight, switching to lamps and dimmer sources into the evening.
I'm always cautious about staying in a room with the main lights on once I've started to wind down, as I can feel myself winding up again.
Here are three places to get blue light glasses for three different budgets (I own each set myself):
Low price: Amazon
High price: Taylor Morris