So, correct me if I'm wrong, but I think the only time you're wasting your SP is if you don't vote when you're at a full 100%. Here's the calculation:
Let's say your 100% vote is worth $1
You could vote once every 2.4 hours (exactly) (10 times/day) and, in 1 week, you'd have distributed rewards worth 10x7x1=$70, and have 100% power at the end of the first week.
OR you could vote every 10 times in the first minute of the first hour each day
100
98
96.04
94.1192
92.236816
90.39207968
88.5842380864
86.8125533247
85.0763022582
83.374776213
You know, what? This is long enough that I just went ahead and made a post! I've seen this line of thinking before and, well, I'm responding for a perceived need.
https://steemit.com/steemit/@improv/math-and-steemit-voting-power