I'm mid-homework and I came upon following sentence: "Seine Mutter ist (nurse)." Should I write "die", "eine" or simply "Krankenschwester"? And why?
If you want to point at one specific nurse or there is just one then "die Krankenschwester" is the correct term. -> His mother is the nurse.
Otherwise you want to say "(eine) Krankenschwester". If you just want to say the job/profession you can omit the "eine", that is what I mean by using paratheses. -> His mother is a nurse. As far as I know it is never wrong if you don't omit it, though.
I dont know if my explanations are understandable, tell me if anything is unclear.
It was the same for me, I had a streak well over a year and then I let it drop on purpose because I saw that I really just wanted my streak to stay instead of actual learning something. I "cheated" with doing easy lessons again if I wanted a break etc.
Conclusion: A streak isn't anything I want or need, but everyone is motivated differently so do what you feel is best for you.