I usually get 2 or 3 runs out of a given item of kit and it takes up to a couple of weeks to get through the whole lot and do a major wash. If it gets muddy or wet then it usually goes in the wash straightaway. I don't seem to generate too bad a smell and do a lot of my running alone so it's not caused any serious offence as yet.
I'm a quick wash man by the way unless theres some serious mud involved.
My feet don't get smelly either - socks are only ever worn for one run.
I'd comment on north country boys laundering habits but since he's usually behind me I can't!
Can't believe I'm wasting some dinner hour writing this....