Pretty neat website you got there!

Knocking through a bunch of exercises every day feels efficient but it's not exactly fun and I put in less time than I should.

I've been reviewing Anki pretty much daily for the past couple of years, and I put in enough time to have all my cards reviewed. What helps:

• Doing it on my smartphones at times were I can't do much else anyway (in public transport, waiting in a queue); the most "productive" thing I could be doing with that time is reading a book, and even then, reading a book standing up is more of a hassle than looking at my smarphone.
• All the stuff in it is stuff I added myself and considered worth learning, and if I have doubts about something (a card or a whole deck), i'll often suspend or delete it
• "Finish today's cards" is a reachable, definite, objective (more so than "a bunch of exercises") but I still don't put big pressure on myself, since if I'm too busy to review today, I'll review a bit more tomorrow, and eventually catch up (I don't need to explicitly decide "I'll review some more to compensate", I just will have more due cards tomorrow).
• I only add new cards if I don't feel overwhelmed by the daily review schedule

(and yes, I've been using this to learn Japanese and to review my Mandarin and German)