SHOULD I KEEP DEFAULT SETTINGS IN NISS 2010

Hello - IE8/SP3/ NISS 2010 VER. 17.7.0.12

                Just did an  'upgrade' install over NISS 2009 other day - things seem to be o.k. ...current subscription will expire in about three months.

               I  Would appreciate guidance regarding the settings=choices for best performance within all sections of the program...... i could leave the 'defaults' for all categories i guess but i did turn-off ''power saving' in "MISC' section since i always use a PC - never run on a battery ...but i'm confused because i thought i read that by doing that,  the 'off' position will  interfer with ''idle full scan'' (or is it if 'power saving' is 'on' that's what interfers with the idle full scan ?!)

           I was confused thinking the ''on'' setting showing for ''power-saving'' caused the word ''never' to show in the 'status' section (Norton Tasks) for ''Idle full scan''..   but maybe that's because i didn't have this new upgrade  in place for a 'full' week' ?  

               Also, when i disabled 'power saving' , there was a 'battery icon' showing in the 'status' section ...

                 Also, if i do a manual-full system scan occasionally, will that ''mute-out' the need for ''idle time scan' to function on a given time (right now it's set to 1x a week ... guess you can tell i'm totally confused.

               I appreciate any advices.....thanks so much Edythe.....