Agree with Chesty Morgan,
After a my HSI failed using my IR skill test I never leave a needle untuned.
Use them all the time enroute and terminal area unless we are doing a VOR approach. When enroute with the FMS auto tuning it is nice to see the RDMI saying you are where the FMS says you are and if they don't then a quick nav check and look for reasons why. In my experience, when in range during the day their accuracy is acceptable. I also often monitor the ADF on approach, they do wave around a bit but I can see in comparison to the ILS or VOR that they are sufficient for a safe approach.