Good recent thread on the DT Swiss hubs leaves me thinking about my own hubs which are making a bit of noise. For those with WI hubs, or knowledgeable thereof, how frequently do these need to be cleaned and re-lubed in a dry climate? I've got 7000 miles on the tandem and while it's in the shop this week they are going to trouble shoot a strange noise coming from the hub, but in the future I'd like to do my own service on a regular basis.