Many professional writers use timeline charts as part of their storyboarding or outlining process. They take each person in the story, for instance, and write a timeline of their events in sequence. What time of year it happens (season), then what day, then what time of day. It seems nit-picky when you're in early drafts, and I don't usually pay much attention at that stage, but in later revision it's essential.
A timeline chart might be as simple as the character's name, the scene, and three columns for (1) season, (2) day of the week, and (3) time of day. If events are hourly in your book, if they are even day after day, your total timeline might span a week or a month or a year. But if you are covering huge swatches of time, you'll really need this kind of time marking for yourself, so you know if three years have passed or a decade.
Once you have your timeline chart in place, there's a great sense of relief. At least for me. But then, as we write, we often lose track of the chart and move time all over the place. A scene starts out in daylight then suddenly there's a point where something is discovered by flashlight. Unless there's a time marker, showing that we've moved into nighttime, the reader will stop, possibly go back and reread (never a good thing), or put down the book altogether.
I know this happens to me a lot. I have my timeline chart but as I move into later drafts, I ignore it. Hence, the need for readers to catch this--if I can't do it myself.
Time markers can be obvious or subtle. Obvious time markers might be "Three days had passed with no word from Ella" or "Had it only been yesterday?" Clunky when you're writing them, but an instant relief for your reader. Now we know if the previous chapter happened two days or a week ago.
Subtler time markers include a sense of changing light in a room or space, the beginning of darkness outside and need for man-made light, how a person is dressed (which can show time of day or season), sleep and waking moments, and much more.
Stuff like this is tedious to keep track of. Most writers dislike it and ignore it. But nothing stumbles a reader faster.
Your writing exercise this week is to either try the timeline chart for one of your characters or scan 3-4 chapters or scenes to get acquainted with how you are using time in your story.