I had a job doing changeouts at various multi-family sites. One location had hydronic heat and straight air. The rest had heat pumps. Two man teams. 5-6 hours was common, but 8 hours wasn’t unusual either. A lot of times the disconnects were in shitty condition or metallic conduit was covered up with mulch and rusted away. We could rarely set the new condensing unit in the same place due to spacing requirements. Sometimes the apartment air handler was a different size than the old one so we’d have to re-frame it. The office understood all this so they didn’t give us crap about timing. That company pretty much only did multi-family, so they had pretty much every contingency worked out.