I’ve only moved 25 gallons and under, and while it was fairly easy for me it was also very little (comparatively) and a short distance. The moment you need more than 1 other person to move stuff, or it’s logistically difficult, is when you should consider hiring a company. I wouldn’t trust 3+ other people to not accidentally bump into something, and it would be unfair to expect that out of them. The extra money it costs to pay a company also comes with that extra peace of mind in those what-if situations.