In reply to im off:
History - When I was at school (80s), for a time, the NHS used to 'build up' my shoes, i.e. they glued sculpted cork into them to treat mild over-pronation. I think the theory was that if it was caught early all you needed to do was get feet/bones in correct alignment and as you grow the alignment eventually sticks. They stopped doing it after a while - I have no memory of whether I just stopped going (getting taken by mum to be more accurate) or if I was ever actually signed off as fixed.... Fast forward to my late 20s and I realised I was getting all sorts of ankle/knee pain and longevity issues in my mountaineering (main sport at time). Penny dropped and for running at least I started using over-pronation specific shoes. Didn't make much difference, good to start with but wore out very quickly and still issues doing long and hard mountain days/multi days.
So went to podiatrist and they did the carbon orthotics. I wear them pretty much constantly and have used for almost 15 years now. Not sure I believe the making things worse theory as my joints have been perfect ever since, they were not perfect before and they have got no worse since as far as I can tell. As they are half/three quarter length size they go in and out of whatever I'm wearing very easy. It's just total habit to take out of what I'm wearing and put into whatever I'm about to put on. Probably easier actually than if I only used them in specific circumstances as I'd be more likely to forget or not have them to hand. I do cope fine without - if I'm dodging around the garden/doing DIY or whatever I just chuck on whatever wellies/old trainers etc come to hand. But work shoes, road and trail running, ski boots, hiking boots etc I wear. I don't in rock boots..... On skis you can actually see that when I don't have them I'm trending towards being on the inside edges of the skis, when I do wear, I'm a lot more level along the length of the ski.
As far as bare foot running, and the whole theory of going natural etc... I'm afraid I'm in the camp that most of what we wear day in day out it is thoroughly unnatural and we have all messed our feet up from an early age. Simply going all out to go 'back to nature' doesn't mean to me that my feet, bones, joints etc are ever going to cope... I know that mankind has run hundreds of miles without any shoes... but aboriginal man didn't spend his formative years in school shoes etc... and there is no historical record of how many had bad joints and pain issues! Just because some did amazing things, not all did.
I did a few hundred kms for example in Salomon Fellraisers. Loved the fit, feel and performance but was crippled with super tight calf muscles. Thought at time it was just as I was really beginning to push up into ultra training for first time but it never got better. Circa 1,000km later and I went onto Speedcross instead which has a heel to toe drop a fair bit greater than the Fellraisers. Problem solved. So, despite giving it a pretty good try it seems my body did not want me in low drop shoes. I'll go with what makes my body work, not try to change my geometry now..... So that means decent heel to toe drop and orthotics. My average annual spend on check up and occasional refurb is probably less than what I save in my running shoes lasting a very long time now and ease of shopping around vs. trying to get the correct corrective running shoe every time.