Rich,
Yes, volume matters in both speakers and caps.
If you saying that you are burning in speakers then they should be as loud as you listen, maybe a little higher to really flex the suspension. A hundred hours should get you most of the way there, 200 if they are Louthers (some say a lifetime). It isn't a linear thing and I expect there is a curve where you get most of the burn in, in 72 hours, then almost all the way there in 100 hours.
If it is caps see the link. The better they are the longer it takes. I have had two friends relate a birth like experience when listening to Teflon caps that already had 100 hours on them. This happened weeks, maybe months, after they were burned in. It depends on how much you play them after burn in. I'm doing Teflons for 200 hours now.