No mention of Anki? I use it every day for basically everything (foreign languages, life memories, trivia, world capitals, etc.) and it's unquestionably changed my life.
I successfully developed a habit for "quick" questions, where you know the answer instantly once you learned it. Examples: Capital of Malaysia? "Car" in chinese? Phone number of Mom? Images work well, like "what country does this map show?"
For heavy questions the repetition feels like too much work. Deriving equations is probably heavy. Another example would be: List all states of the US.
Deriving equations is not fun for my mind, because it takes seconds or minutes of concentration. For the quick questions, I receive success dopamin before I even notice that it is work. Fun. It becomes a game and I sometimes did a few cards on my smartphone while waiting, for example.
One strategy is to split heavy questions into many quick ones. Unfortunately, I don't know what to do if splitting does not work.
This helps me pause before browsing (should I really be looking at that?) and also study somewhat frequently.
It’s not entirely different than looking at old photos, but the SRS system keeps the memory fresh.
Memory freshening can be used responsibly, as part of a balanced mental diet. However...
I saw a paper go by years ago, on someone who seemed to have outlier excellent memory retention. They could tell you what they did on arbitrary days decades past. It turned out they were just an expert on their own life, spending much time each day refreshing memories.
Less extreme, the story of an elderly widower, who would sit out each day, replaying memories of time with his wife. Each like a little dopamine hit, no app required.
It's called Hyperthymesia [0], the actress Marilu Henner has it and "can remember specific details of virtually every day of her life since she was a small child" [1]
[0] https://en.wikipedia.org/wiki/Hyperthymesia
[1] https://en.wikipedia.org/wiki/Marilu_Henner#Personal_life
Accumulate knowledge in intervals?
SRS (with Anki or not) schedules reviews to try to help you remember. You study 100 facts today. Tomorrow you review them all (this is actually a bit much for someone just starting, but go with it). You get 50 correct, you'll see them again in 2 days. You get 50 wrong, you'll see them again the next day. Eventually, everything you've studied for a long time will either be scheduled for reviews way far out in the future, or you'll be reviewing it frequently (which often means the card is too hard or you otherwise just aren't getting it). You edit the card to break it down ("Columbus sailed on the Pinta, Santa Maria, and Niña in 1492 from Spain.", that's at least 6 facts: name, ships, year, origin).
This is better than the alternative, and the way many of us (or at least my classmates and I) did it in school. We made flashcards and just reviewed all of them over and over again. It was a long slog to get through, and often we'd just skip it rather than deal with it. Or the ones at the bottom of the stack would never get reviewed properly. SRS works in much the same way, but you don't review the full deck each day or even each week. If you learn a fact really well, you won't see it again for months. If you still know it then, you won't see it again until the next year. So the only things you study regularly are new things, or things that aren't (for some reason) sticking.
Anki is a useful (and free) application that will sync across your computers and devices (I make cards on my laptop, but review them on my phone) that implements SRS. You can, through plugins, do a lot of neat things like autogenerate math problems so you aren't practicing the same ones over and over (and risk just memorizing them rather than learning the techniques), or have it render LaTeX to the card. It'll show images, play audio, and more.