Regarding Vision. Them all the time?

I am 19 Years Old. I started Wearing Spectacles 2 Months Back for the first time. Initially on my first consultation with a doctor, I was prescribed with -0.25D cylindrical in Left Eye and -0.5D Cylindrical in Right Eye. Then the next day on my second consultation with another doctor I was prescribed-0.75D cylindrical in Both Eyes. Both the Doctors gave me cylindrical power only. However, I am currently wearing -0.25D cylindrical and -0.5D cylindrical prescription and I am comfortable with this one. I am constantly wearing specs for the last 2 months. However, I had a few questions. 1. Do I Now have to wear the spectacles all the time, 24×7? I mean for most of the day? 2. If I don't wear spectacles all the time, Is it going to make my eyes weaker? 3. Is wearing it going to make my eyes more weak? I also want to know that if I have to wear them all the time? And if there's any risk in not wearing them all the time. And how can I Improve my vision. Hoping to hear from you & thank you