This. TIPS track actual, not average historical inflation (as measured by CPI), don't they?
That's of course true, but don't you think that 'personal' inflation will usually be reasonably close to CPI? Especially if you are willing to make some adjustments? The one exception I could think of is if you are renting in a booming housing market. That could be a major item on your budget going up way more then CPI. But apart from that? If you own your primary residence (as I suppose most posters here do), mortgage-free or with a longer-term, fixed rate mortgage, I would expect your personal inflation to be close to (or usually below) CPI.
I know that our personal inflation rate is very low. Single biggest item is the mortgage, and that is fixed for the next ten years. Now if beer increases ten-fold, guess I'll drink more scotch instead.