When to replace shoes?

[jwrushman]

I have a pair of Pearl Izumi X-Alp Seek SPD mountain bike shoes I use for touring.  I like them because they (kinda) look like regular shoes and have a recessed cleat to allow for easy walking.  When should they be replaced?  Should it be based on age? Miles? Or a combination of both?  I've had no foot problems so far, but the shoes are 3 years old.

[John Nettles]

Since a cycling shoe should have a fairly stiff sole to increase the pedaling efficiency, I replace mine when the sole becomes too flexible (relative to where it should be).  A hard-core racing shoe should not flex at all while some touring shoes flex a lot (at least to what I think they should).
Walking in the shoes probably causes them to soften quicker so trying to base on miles is a bit difficult, i.e. do you stop every 5 miles or every 50 miles.  Do you walk around tourist sites in them or just around a convenience store?
Hope this helps, John

[Nyimbo]

 I usually replace my SPD cleats after a year of regular riding sometimes the shoes last through 2 sets of cleats.  I really don’t know if it’s necessary but I read you should change them periodically  when I first started cycling and I’ve done that ever since.  seems like the price is between 10 and 20 bucks so it’s not too expensive. The shoes for me I can usually just tell they’re worn out just like I can any pair shoes they just feel or look worn out. (Subjective answer I know)

[Pat Lamb]

Good bike shoes wear out, eventually.  I think they're like bottom brackets -- check them occasionally, and replace when they need it.  Three years is almost new.

I replaced my Sidi MTB shoes this year after 9 years of riding.  To be honest, I could have replaced them 4-5 years sooner based on lug wear that exposed the cleat, but being cheap (fun to say when you're talking about $200 shoes!), I built the lugs up with Shoe Goo for years.  I don't do a lot of hiking in bike shoes (other than in and out of work for bike commuting).

That makes a total of two pairs of shoes I replaced because I couldn't get the cleat off, one pair where the lugs were worn down too far to fix, and one pair where the sole came off the upper (fun ride, that one!).  That makes an average of 20,000 miles plus per pair.  Good bike shoes last a long time.

[oldguybiker]

I always thought a touring or MTB shoe should flex outward or in a convex direction to allow walking, but not flex inward or concave.
When cranking hard, if the pedal or cleat creates an uncomfortable pressure point against your foot, its time for a new pair.  As long as the shoe distributes the force of the pedal or cleat evenly against the foot and otherwise functions well, I keep using them.