There's an easy hack for the contact lens (and maybe glasses?) situation. There is a consumer protection law meant to ensure eye doctors can't stop you from using any retailer you want (otherwise they'd essentially make themselves your retailer), and it works like this:

You place an order with the retailer (online retailers typically allow you to simply type in your prescription values when adding lenses to your online cart; you don't need to show an official written prescription) and specify your doctor's name and phone number. Upon receiving your order, the retailer must call the doctor to see whether the doctor objects (invalid prescription). The retailer is to ship the order only if there is no objection (including no response at all) within 8 business hours. So just give the retailer the name and number of someone who won't immediately object, which is quite easy (e.g. a permanently closed office).

Of course, you need a refraction to know your prescription values. But once that's done, if your vision doesn't change over time, this allows you to ignore the expiration date of the prescription.