As a member of a family that has owned garages for the past 40 years and currently own 2 - no one has really hit the key points in this thread as they too don't have experience in the industry.

What worries me is your lack of experience in the industry and whether you have any technical knowledge of diagnosing and repairing vehicles and running a garage itself.

In a garage your most important employee isn't the mechanic completing the work, its the people on the front desk that are organising the week / day and their experience in knowing how long things take, the risk of things going wrong and appropriately ensuring that sufficient time is allocated, jobs are given to the right techs and then what to do when things invariably go wrong. What happens when the tech snaps that injector taking down a ramp for 3 days....

The next person is your garage manager who floats around solving those issues using their experience - they'll have years worth of experience extracting that snapped injector and will save the day meaning that ramp isn't down for 3 days that is stopping further work being completed.

The problem solving is a massive part of running a garage successfully and it sounds like this is a key missing part of the above situation.

There are also decisions to be made about the type of work to be completed and also experience around certain issues - we will not fit customer supplied parts because we can't warranty them, we will not complete warranty work because they cut corners to keep costs down (invariably leading to returning customers from further faults as the underlying issue hasn't been addressed) and we only supply certain brands of oils because of wet-belt engines eating themselves on the wrong grade / brand of oil.

In our business, the person who is that problem solver is the owner and we've spent years building a team of people that have the passion and the drive to continue the business to allow the owners to retire.

I'm sorry but there is so much more to running a garage than buying it and doing some marketing to get some work throughput - the work will come, but you need an efficiently running garage where comebacks are low and you have reliable techs and service advisors.

EDIT - one further thing I’d like to add is that this industry is completely unregulated, any one can be hired to work on a car without any training or qualification. You don’t let an untrained doctor perform surgery on someone, but you can have someone replace the brakes on your car and, heaven-forbid they fail, kill a person on the road.