Gait analysis really good. I have never run in my life but decided I needed to get off the sofa. Went and got running shoes from a gait analysis place (OK I'll be honest here - the shop had parking outside - I wasn't up for taking the 1 and 5 year old on a bus), tried several, bought a pair two sizes bigger than I take in regular shoes on their advice and I can honestly say when I run/lollop I don't notice my feet at all, they are very comfortable and my feet never hurt or ache afterwards. Worth it.
Are your old shoes comfy? If you can't get a gait analysis where you live, try Nike customer services and you may be able to find out whether your current shoes are neutral or extra-support or whatever. My running shoes are also really old and Nike were really helpful and let me know the model name for the current equivalent of my shoes.