I know that the SPL meter is crucial to setting up my HT properly, but Im just wondering, once you calibrate it, is tehre really a use for it after? I mean, when will you realy need to use it again if you dont plan on adjusting the speaker placement? I ask this because my dad's friend has a SPL meter he was thinking of selling, but is willing to just let us borrow it. It dotn really want to keep asking him to borrow it again if for some reason I DO need to calibrate again, but then im thinking how often do i need to calibrate. Thoughts? Should i buy it off him for cheap (prolly bout $20, $25 CAD), or just borrow it once, and record the speaker volume settings?