You may not realize this, but if you own a smartphone, it comes with a step counter. Because it tries to count steps while in your pocket. (my son can explain to you how step counters work). But the magic in step counting is not being able to count steps, it is mental, it gets you to be more active based on the "if it gets measured it gets done" principle. Meaning you actually have to look at the numbers every now and then to get the motivation to do something about it.
So, I'm a lapsed runner, but I run a decent amount. I got my iphone 5 somewhere in 2017 (I think) and that is when I now got Apple Health, which lets me see the iPhone step counter. So this is what it shows me for those first few months.
So, I'm hovering around 5,000 steps per day. But I'm not paying that close attention. In early 2018, I get a fitness tracker. A Huawei Fit, because I want it to double as a watch. And it has an immediate effect. I start actually looking at my step count. And realize that the only thing between me and a consistent 5,000 steps a day is taking the stairs 10 flights to my office. And I start doing that every day, at least once. Because when I do that, 5,000 steps in a day is easy.
Now, 5,000 steps per day is easy. But I actually do real stuff. Like CrossFit, taekwondo, and I occasionally run. And I realize I am actually getting use out the fitness tracker, so I figure it is worth getting a real sports heart rate monitor. Being a former runner (and I already have a Polar H7 chest strap), I stay in the Polar ecosystem (because Polar's definining trait is that it caters to athletes and does not have anything that an athlete does not need) and get a Polar M200. Because it is already generations out of date and I can pick it up for pretty cheap. And then this is what happens around December 2019 (early Christmas present)
Another jump. Actually, Polar does not actually reports steps, it reports activity, which is much more useful. So, instead of thinking about whether or not I am walking up and down 10 flights of stairs, I'm more interested in making sure I take activity breaks (to avoid movement alarms), and getting my activity(ies) in every day.
So, I am a poster child for how having a gadget gets someone to be more active. And in the era of COVID-19, you can see that April was when we all went into stay at home, and by the next month I had my routine set (10 minute exercise sessions in the morning and around lunch to replace walking up and down the office stairs, and I get my main activity in the evening). And yes, I think I am making my heart rate monitor worth it.