Shoe choice is often sold as injury prevention: stability shoes for flat feet, cushioning for heavy runners, minimal shoes for natural running. The research is less clear than shop advice.
What seems reasonable:
Matching shoes to foot type alone has not reliably prevented injuries in studies
Comfort appears to be a reasonable guide; a shoe that feels good to you is a sensible starting point
Big, sudden changes (for example, switching to minimal or very different shoes) should be made gradually, as they shift load to different tissues
Training load errors are probably a bigger factor than footwear for most running injuries
Rotating two different pairs is a common habit, and some research hints it may be linked with fewer injuries, though that is not proven. At least it means no single pair takes all your mileage.
Many runners replace shoes somewhere around 500-800 km, but it varies with the shoe and the runner. Visible wear and a change in feel are better guides than a fixed number.