a long time ago i did a wrietup on this for a friend as a private conversation.
in brief, consider the following:
Rent, legal fees for bookkeeping, and salary are your 3 biggest overhead concerns.
below that you have the cost of manufacturing which is your water, hydro, data storage & management, consumables such as stone and powder investment and refined precious metals.
the lowest costs are the fixed costs or equipment loans. these can be recurring fees but once they are paid they are done. granted nothing lasts forever, but theres plenty of opportunity to pay off a piece of equipment before it blows up.
for a 1-scanner, 1-oven, 1-mill setup, you will spend roughly 80-100k. cut corners and cheap out if you like but a good system is roughly that much. financed over 5 years or lease to own, and youve got a nice low monthly payment.
working up, the recurring cost of manufacturing can be budgeted if you know your sales volume. one box of stone per month means you wont be making a lot of cases, but two boxes affords a lot more work, and some breathing room should the worst happen and remakes are required. this is but one example.
salaries should not surpass 40% of your volume. i.e. if the lab makes 10k per month, your salary and the combined salaries of everyone in your employ should not exceed 4k. so you already see how you will need to either employ nobody, or do in excess of triple that sales figure to employ one person and pay yourself a six figure salary.
top of the board you have your taxes and rent. industrial units can be difficult if they know you want to rent long term, they will strongarm you into 3k-5k rent bills because they know you will be around, and have grounds to sue if you terminate lease agreements early. be careful about it.
so for a 1-mill 1-scanner 1-oven setup you need a 25k per month income to consider opening your own lab and make 55k in salary and be comfortable. but it means you will work every day and lose business if people like myself eventually manage to sell technology solutions to your clients under the guise of saving lab bills.
\\rubs hands maniacally.