I don't think the bottom of a mug is capable of enough precision to make the Sharpie trick worthwhile (or even (=flat) enough to talk about choosing bevel angles), but here is more info about knife sharpening than most people need :-)
It's never going to give you as consistent an angle as a water stone is, certainly. But I'd still expect a difference if you tried to bevel one knife to 30 degrees and the next to 12.
You may be right about the Sharpie trick.
What can I purchase with $100 that will be the best thing I can buy to make my life better?
I've decided to budget some regular money to improving my life each month. I'd like to start with low hanging fruit for obvious reasons - but when I sat down to think of improvements, I found myself thinking of the same old things I'd already been planning to do anyway... and I'd like out of that rut.
Constraints/more info:
Background:
This is a question I recently posed to my local Less Wrong group and we came up with a few good ideas, so I thought I'd share the discussion with the wider community and see what we can come up with. I'll add the list we came up with later on in the comments...
It'd be great to have a repository of low-hanging fruit for things that can be solved with (relatively affordable) amounts of money. I'd personally like to go through the list - look at candidates that sound like they'd be really useful to me and then make a prioritised list of what to work on first.