Refurbishments happen all the time. The resorts will take rooms out of service regularly to paint, wallpaper and replace carpeting. They will swap in replacement appliances, mattresses, linens, furniture and fixtures as needed.
Now, if you're talking about major work, I would probably classify that as more of a "renovation" than a refurbishment. If you're looking for newly-designed rooms (i.e. new style fixtures, new linens, flat panel tv, armoire, etc.), don't expect that to happen very often. Last time I looked at my resort budget (SSR), I believe there were accommodations in the capital reserves to do those sorts of things around halfway thru its lifespan. If the same holds true for VWL, you're probably 12-15 years away from it happening.
That's not to say that they won't move to something like the flat panel TVs much sooner than that. AFAIK, most of the resorts' sofa beds have been upgraded to better models over the past 3-4 years. DVD players are being added to Studio villas. Replacement mattresses are of higher quality. Likewise TVs don't last forever and at some point they will certainly start phasing-out old technology in favor of the new.