I think shoes are worth spending a lot on especially if your job keeps you from sitting down for most of the day. I think it's essential to spend on shoes because otherwise you just end up getting sore or worse you might even cause damage to your posture. Also, expensive shoes usually tend to last longer anyway so you're not really paying that much considering you get to use it for longer than you would cheaper ones.
I like to invest in good shoes. I'm a teacher so I'm on my feet all the time, a good pair of comfortable shoes are a must. I have several pairs of leather shoes that I've had for over 15 years and they are still in great shape and they are a classic oxford shoe so they never go out of style. I like to shop at outlets so I always look for shoes on sale too.
Good investment pieces are coats and suits. Good quality shoes are important for comfort and to make sure your feet are healthy, but shoes don't last forever unless they are high heels. I spend more on coats because they can last a lifetime and suits have to be well tailored to fit well and generally the more expensive ones fit better and the quality of the fabri is more durable.