Unless I'm in a cafe, hotel or staying at someone's home I connect to the internet over a tethered connection to my smartphone. I've got an unlimited data plan--but only the first five gigabytes of information that I send or receive is at LTE speeds. After that, things turn slow as molasses flowing uphill in January. To try and keep my data useage under control and, thus, my speeds higher for as long as possible, I use an application called TripMode 2. It's available for MacOS and Windows ten and, priced at eight bucks, it's ridiculously inexpensive to purchase a copy.
Once installed, TripMode is stupid easy to use. Activate the app, locate it in your Menu Bar (MacOS) and click it to get at its drop-down menu. There you'll see every piece of software on your computer that's begging for access to the interwebz. If you're not using the apps you see on the list, de-select the check mark next to it. Boom, they're cut off from using your tethered device's data. You'll note that at the bottom of the list, you can see how much data you've used since you started your session, during the course of a day, month or year. If you're on a plan with limited data, having that information is pure gold.
Best of all, when you're not using it, TripMode 2 can easy be shut off. It's easily up there with Scrivener, ProtonMail Bridge and Adobe Lightroom as one of the most important bits of software that I use on a regular basis.