Take things that happen every time with regularity, and make them not happen, so you can remember the last time they did not happen.
For example, consume things; I have a regular morning routine I've kept for 30 years, but it isn't precisely regular: I run out of coffee, or filters, or shampoo or toilet tissue, or the coffee pot dies. In thirty years, I've had two plumbing problems. You wake up on a few mornings and the electrical power is off. for all of these, you can remember the last time that happened.
You are also consuming time: For you in a few months, the season is changing, and the morning temperature changes, getting colder or getting warmer. Some days it is raining outside, or foggy, or snowing, or some days there are birds singing, the yellow roses are blooming. You see your neighbor's garden outside the kitchen window. If you start in Winter, close to Spring you see the garden start to thaw and green.
You may also be consuming people in this regularity:
When the garden changes, you see your neighbor Karen out there for the time in months, and she waves at you: Like she will every single morning, barring rain, until she once again shuts the garden down for the winter.
Your routine is on the bus, or you stop at a Starbucks. All the usual suspects are there. You may not know any of them, You may have a nodding recognition, but on various days one of the regulars is missing, or something is slightly different. The trenchcoat kid in the front left seat gets off at 23rd street instead of 31st. He's gotten off at 31st every day for two years, wtf trenchcoat kid? New job, or just an odd errand?
Heavy man is asleep in his seat this morning, that's different. Gray lady, two seats behind him, rises two minutes before they reach Heavy man's stop and shakes his shoulder, he wakes up, shakes his head awake, and then hurriedly packs his laptop and gets it back into that worn briefcase, ready to depart. She retakes her seat without a word.
The same things happen in the coffee shop; they messed something up and have no blueberry danish.
At the gym, the regulars change, quit, make progress.
The world is constantly changing, even if it is just the climate, and life happens. We get a cold, we consume things, we run out of things. We have unusual appointments to keep: A doctor or dentist appointment, dealing with the car mechanic or pest control, broken things to be fixed. Or you stayed up too late watching a game, or playing a game, or had a date.
No routine is completely stable and identical every single morning, every once in a while they get broken or interrupted.
More importantly, nearly all of us have some regular routines, so you can take advantage of other people's broken regularity to mark time in your own. Mike the coffee shop barista that has been there for a year is suddenly not, and the new guy screws up your order.
The bus driver changes, or there is some new weird guy on the bus. The gym manager changes, or somebody new shows up and has taken your treadmill.
You can allude to the routines; IRL they become part of muscle memory and you can do them without thinking about them, and while thinking of other things. It is the interruptions that are of note. If you just want to indicate the passage of time, these can be minor.
But you can make them part of the plot:
Karen starts to make coffee in the morning, and her tap water is off. A main must have broken. She resorts to using four bottles of her drinking water instead, which puts her behind ten minutes. She can't take a shower, so it will be a washrag affair with another six bottles. She needs to wash and rinse her hair. Which means she has to go buy more drinking water, off schedule, putting her in the grocery store on a Wednesday evening, instead of her usual Saturday morning. And there she sees --- one of her nodding acquaintances at the morning donut shop, an attractive young man that she knows owns exactly three good looking suits and is always in a hurry, and wears no ring. Now he is dressed in new jeans, a worn T-shirt with an engineering diagram of a Model T on it, and new sneakers. She makes an impulsive decision to get behind him in the checkout line.
"Hello, two lemon filled," she said.
The young man turns, surprised. "Ah. Apple Fritter. What finds you here?"
Karen gestures at her basket. "Water, my main was out this morning and I used all my drinking water." She offered a hand, "I'm Karen."
He took it, "Warren. Or lemon filled, as you see fit."