-superfeet recommends 12 months of active use. sometimes more, sometimes less. it depends a lot on the individual person. (a heavier runner will break it down quicker, etc.)
-The top cover tends to wear before the plastic cap on the bottom of the shoe. If it's too worn the support will be "off center".
-If you see noticeable creases or white "stress lines" on the green cap on the bottom of the insole.
-i've always been told by various people who have helped me in running stores that "2 pairs of shoes" is a good rule of thumb. If you replace your shoes every 500+ miles then that's about 1000+ per superfeet. You're at 5000+, which seems a tad bit excessive for a $40 piece of plastic and foam. Keep in mind that these aren't custom-made personal orthotics and shouldn't be expected to last as long.
My suggestion is to go to a store that has a try on pair and see if a new one feels better in your shoes. I ended up buying a new pair but still used the old one in walking shoes and shoes for yard work.