Thank you for sharing those 2 links. I will definitely read both.
I will keep the current setup (1GB RAM and 25GB disk space) for now, but I will definitely upgrade to the 2GB RAM and 50GB disk space pretty soon, when things start getting a bit busier.
(I did manage for some years to run a small forum on 20G and a medium-small one on 25G, but I have since moved to an offering with 40G storage which has allowed me to relax a lot about upgrading.)
Yeah. Sorry. It’s a lot to take in when you get started.
I’m using Digital Ocean, and upgrading is a bit “tricky”, because if I move to the next plan with more space, which instead of $6 is $8, the CPU type changes to Premium (from Regular). So if I then want to upgrade to the $12 plan, which is 2GB or RAM, I can’t, because that plan is using the Regular CPU type. That means that I would then have to go to a much more expensive plan to match the CPU type. At least that’s the info I got from ChatGPT, since I’m not an expert when it comes to these things, but it made sense to me.
That’s why I rather wait until it justifies upgrading, and go straight to the $12 with 2GB RAM, while still keeping the Regular CPU type, which is the one I have now with the $6 plan.
Always juggling 
No worries. I understand that sometimes when we are comfortable with a certain subject, we tend to say certain things that to us are more obvious, but not for others. It happens with me when it comes to music, which is my job, so I sometimes try to make sure the person understands what I’m saying.
I appreciate all the info here, anyway. Always learning something new.
Indeed, I did the same - stayed with the status quo for as long as it seemed worth the extra effort. I too was with Digital Ocean. I moved to Hetzner, where I get more machine for less money.
I think I agree with your analysis and plan: $12 is the next step, with the current provider.
As I think you’ve found, the limited storage is needed both for swap and for space for the upgrade to do its thing. The upgrade needs more space at the peak than is needed for the steady state. In fact, for that reason, I found myself temporarily moving to a higher-RAM instance for the purpose of the update and then moving back to the cheaper droplet. With a higher-RAM machine, I didn’t need the swap, as I recall.
As time passes, Discourse needs more resources, and the problem gets trickier.
Do be absolutely certain to take and also to download a backup before you start an update. Once you’re certain of the backup, you can (and will quite probably need to) delete all the on-instance backups.
I never used DO’s snapshots - they might have their uses. I think you’d need to stop the database before taking one. And they are an extra-cost option, as I recall.
Digital Ocean was just the one suggested in the official installation page, so I went with it. Since I’m not familiar with many of these things, I just trust the opinions of others. Maybe in the future, with someone who can manage things instead of me, I can find other options, better and hopefully cheaper.
Since I’m still in the process of setting everything up, customizing things and all that, I tend not to worry much about deleting those backups, but I will definitely do that. For now they are like 20MB each, so I didn’t worry much.
With time I will start checking those options as well. See what’s most cost effective and all that. One step at a time.
Thank you for your feedback and help!