I've been reading the How To Brew book, and it (amongst other sites) recommends rehydrating yeast before pitching it.
Some sites suggest adding a teaspoon of sugar with the yeast, others just seem to recommend hydrating. All of them seem to suggest that after 30 mins or so, you should see some visible bubbling etc in the yeast.
I've done about 9 extract brews so far, and tried rehydrating the yeast on the last 3 or 4. However, whenever I try this I never get any response from the yeast - it just sits there looking exactly the same as when I first put it in the water. (Have tried with and without adding sugar). Usually after an hour or so, I'll give up and pour it into the beer which so far has worked fine every time anyway.
Is this step worth doing? Should I be seeing more happening in the yeast than I am? Or am I just not being patient enough?