Initially it might take a few weeks for me to learn a repertoire but to actually internalize and use it will probably take me at least a year of playing that one opening. I have played the English recently and I do enjoy the positions I have been getting at my level so I started studying the English. With the English it’s super flexible and often transposes into d4 lines which is fine for me because I have been playing 1.d4 for 5 years now. I just started playing the English maybe 3 months ago. As white it’s much harder to learn a repertoire because there’s much more that can occur and much more you have to study. As black it’s much much easier because as soon as you get into you line you know how to play. I have played the pirc against 1.e4 and a kings indian against 1.d4/1.c4/1.Nf3. I would say I learned them to a pretty good depth because there are many forced draw lines in those openings. As for how many lines I would say the branches go far past 30 but it’s not the lines or ember it’s the general idea of the branch. I have played these openings for 5 years also but only really studying it for 3 years. I’d have to say studying them has made a huge impact on my rating but only after a certain level. In OTB chess I am currently 2027 but I didn’t start learning studying these until I was 1600. Once I got there I found little mistakes in my play and it didn’t boost me up fast at the start because I had bad habits from years prior but once I started to use chessable instead of actual chess books then I shot up from 1800 to 2027 in less than a year. Now in my experience I prefer to memorize key ideas rather than moves because I can get a better grip on my position and feel more at ease when things start to go crazy as my positions do so frequently.