Re:
This is true, I do them reasonably regularly, it's more because I have a lot of bikes that's the issue.
I usually do them after winter. Although I was doing them more, but I've cut down on how often I was the bikes as I realised I might be washing the grease out, no matter how careful I was with just using the gentle spray setting on the hose. The rear generic hub on my modern bontrager wheels has the most woeful sealing around the freehub and right bearing cup, and it is always full of a brown sludge when I service it.
The main problem I have tho is knowing when to service them, because they're not spectacular hubs they never run particularly smooth no matter how well they are adjusted so it's hard to tell whether they are rough because of this or because of bad grease.