Problem Set Advice

Hey everyone

A few questions regarding problem sets.

Should I do all the problem sets under timed conditions or should I start of without any restrictions?

Should I be worried if I am not improving as I go through the problem sets? Is the main purpose of a problem set to familiarize myself with the questions and strategy or to perfect the subject matter. Over all the problem sets in a section I am averaging around 4/5 with 4.5/5 BR.

Thanks for the help.