1000 words? Well, depends on who's words they are doesn't it.
So I decided to take it a step further... and build a spreadsheet. Mostly because I love spreadsheets:
I started with my SP at the time of the post. Turns out if I let my VP get back up to 100% (it's really hard to not hit that vote button when I see something I like in my feed...) I'm worth about $13 a year on voting value. My 1000 words don't seem to be worth that much... but that's ok. I believe in SteemIt and, to recite the party line, it's more than Facebook ever paid me.
But as you can see, over all it's still keeping to that 19% APY formula (minus compounding SP)... but self voting isn't really worth much at lower levels, especially when your votes can mean much more by voting on good content. Even at an SP of 1500 you're talking about a minimal amount of gains in exchange for irritating people or looking selfish (this is not a universal opinion, but certainly one I've seen expressed). Unless you're prepared to invest 10k or more, save your votes for the good content you find to encourage them to post more of it and grow the community... and who knows, you may get lucky and end up with a fatty curation reward for having done so.