Very helpful answers. Thanks much. BTW- a friend of mine said that different wheels require different spoke tension ranges. True?

My wheels:

Rear - Velocity Dyad 36 spoke count
Front- Salsa Delgado Cross 36 cnt

Not that you guys would have a lot of experience with this because guys my size don't usually commute so much with as much gear....but is it unreasonable that my rear wheel gets out of true within 3-4 commutes? I figure the load on the bike between rider, rack, dual paniers, laptop, clothes/gear, full water bottle, lights etc. etc. is probably 350 pounds.

And when I mentioned above that sometimes the spokes get loose....I'm talking really loose...like I'm surprised it's not detached. Takes several turns to get the tension (through plucking) to even come close to the surrounding spokes. This doesn't happen often but sometimes.

Thanks again.