Clean up memory?

[RJT]

Is there a way to check how much memory I am using at any point in time? If so and/or is there a way to clear stuff in memory that I am not using at the time? I know (think) if I reboot that memory clears and only memory in use is what is needed at start up. Or doesn’t it work that way?

Thanks

[astroglide]

ctrl-shift-esc, performance tab. 'total' under commit charge is how much you are using. if you go to the processes tab and click on 'mem usage' twice it will sort by most memory use (descending order).