Is there a good way to tell if an e-sim is still being used? I have a couple active e-sims going and one of them hasn't gone up in data usage in a few weeks. I want to make the most of my donations and make sure as many people as possible stay connected so if this plan has been abandoned (or worse, obviously, but trying not to think about that) I'll want to just donate a new one, but I'm worried that that user has just been using their data really efficiently or hasn't been relying on it recently and that if I let it expire that'll mean they're out of data
Follow steps for how to tell if your esim has been activated.
The same screen that shows you whether an esim is active should tell you how much data has been used (usually to the nearest 10 megabytes). This is the case for Nomad, Simly, Airalo, and I believe Mogo. Holafly esims are the exception; you will need to contact customer support (in the app: copy the order number from the eSim in question -> go to "Shop" or "My eSIMs" or "Guides" -> click the question mark in the box at the top right of the screen to get to "Help center" -> scroll down to "Contact us" and click "Let's chat"; ask the representative you're connected to to tell you how much data has been used, and tell them that you can't check yourself because it's not installed on your phone).
You may be able to get a more precise number for the amount of data used if you contact customer support for the other apps.
How long you want to wait without apparent data usage before you decide to stop topping up an esim is of course up to you. I have had an eSim appear to start using data again after a pause of about a week, and I've also had a couple that have seemed frozen for months. Once a particular esim starts using data, I tend to get a sense for how quickly data is used--if an esim habitually goes through 1 GB and more a day and then suddently stops, I would tend to assume it's no longer being used. The majority of the esims I currently have active don't use data so slowly that I don't notice the number change at least every 2-3 days, if not every day.
I would recommend buying top-ups in chunks of 2-5 GB. 1 GB seems too small (even with notifications on, I sometimes barely caught that the 1 GB plans or top-ups were active before they ran out of data and expired, so I don't really buy them anymore), and anything larger than 5 GB is risky in terms of potential waste.