I keep tabs, too. I went overbudget last year (not by too much.) Plan on doing better this year by buying just what I need to finish a project rather than add on that extra 1/2 to a yard. And of course only buying fabric I truly love and really good sale items. Well maybe I'll stay underbudget this year?!
I like keeping tabs of 95% of our household expenses. It puts a reality check on what you are spending where. If you want a big ticket item you can see where you can cut to afford it.