When Do You Replace Textiles?

Well, visible wear really.

Or fading colour, waterproof quality failing (try nikwax wash and proof first).

Armour is replaceable if it even has a shelf life.

Or, replace it when you fancy a change, flog the old stuff on local Facebook or eBay

aye, my Rukka kit will only get replaced when I can no longer get into it, nikwax is great.... even used it on a pair of jeans before heading off to Europe on my V7!

I think the recommendation for helmets is because the plastics can degrade over time, and that's basically invisible. Maybe certain constructions can last longer than others, but it's going to be down to you far you want to take it. It'll also be down to the amount you use it as well.

Other thing with helmets is fit. The EPS can compress over time, and you should always think about how well it's still fitting as the above everything guide for a helmet is that it must be a good fit, poor fit,
Poor protection. The well fitting budget helmet is going to do more for you than an ill fitting expensive Schuberth.

As with anything, there's no hard and fast rule, use your common sense, if you're a 365 rider then you're more likely to need to renew gear in general sooner than the weekend summer rider.