I'll restrict myself to the software/IT sector as that is where my expertise is most prominent. Oboarding and successfully integrating juniors is fully depende

I'll restrict myself to the software/IT sector as that is where my expertise is most prominent. Oboarding and successfully integrating juniors is fully dependent on having real seniors (not juniors that you sell as seniors) in the company and budgeting them substantial time (>25% minimum per trainee supervised) to support this process. This further assumes that you had a decent selective hiring process, as no training/onboarding will compensate for the senior's productive time for complete misses.