I guess it depends on the kind of photography and the effect you want to achieve. If you do studio/object/portrait photography, you’ll probably look for different conditions/set-ups than when you’re a street or landscape photographer.
It’s about light & shadows, colours. For example, if you photograph a city in the middle of the day on a sunny day, your shots will come out with bright colours and high contrast. Go on a grey, but clear day, and the contrast will be less pronounced, the colours duller. Go out early in the day or late at night, when the sun is just starting to rise or set, during golden hour or magic hour, and the lights and colours are completely different, have a more ephemeral quality.
If you’re interested in landscape photography, for example, the best times are usually those: the early and late hours, the sunset and sunrise hours. It gives the landscape a more mysterious aura. If that’s the effect you want to achieve, at least.
A good exercise might be to go to the same spot on different times to photograph the same scene. Early in the day, or at night, during magic/blue/golden hour, when it’s raining, or just overcast, in the middle of the day when the sun is shining bright… You’ll get a feel of how the light changes, how it affects your photos and what you like best.
It’s not because some people describe their lack of skill as self-expression, that the concept in itself is bullshit, though. As we say in my mother language, don’t throw away the baby with the dirty bath water. :p