I have seen MANY junior techs replace hoses just because the O-rings were leaking. Every decent hose manufacturer sells replacement O-rings so you can keep those hoses in service until the hoses themselves become damaged.
Here are some more tips to make it easy.
- Use a little (a tiny bit) of refrigerant oil or Nylog on your hose connections and seals to keep them well conditioned.
- Check your hoses before attaching them every time. In my experience most seals become damaged because they get a little out of place and then get installed anyway, crushing and damaging the seal.
- Don’t over tighten your hoses, if you need to use channel locks you are doing it wrong.
- When you buy hoses or a manifold, get extra seals at the same time.
- Use the same brand of hoses on all your manifolds, recovery and evacuation kits so that you can keep extra seals for all of them on the truck.
- Keep your loose hoses capped with brass caps on each end to keep the seals from drying out and your hoses clean and dry.