Equipment can be acquired in three ways, and the difference is how it is paid for rather than what it costs to own.
Buying outright
Consumes cash immediately and produces an asset the business owns.
The cash is the constraint: a purchase that leaves too little working capital is a risk regardless of how sound the equipment is.
The cost reaches the profit and loss over years through depreciation, not in the month of purchase.
Financing
A loan secured on the equipment. Cash is preserved, a monthly payment is created, and interest is paid.
The payment belongs on the debt schedule and counts toward debt service coverage, which affects the ability to borrow again.
Only the interest is a cost; the principal is repayment. This is why financed equipment can be profitable on paper and still tight on cash — see amortization.
Leasing
Payments for use over a term, with the equipment returned or purchased at the end.
It avoids the residual value risk and generally costs more across the term. It suits equipment that dates quickly, and suits a business that would rather hold its cash.
Accelerated deductions
Tax rules allow some equipment purchases to be deducted immediately rather than depreciated over years, which can substantially change the after-tax cost.
Eligibility, limits and how they interact with financing and leasing are specific and change between tax years. This is a question for an accountant before the purchase, not after it.
The prior question
Whether the equipment earns more than it costs. Financing makes an unaffordable purchase possible; it does not make an unwise one sound.
The test is the additional work it enables against the total cost of ownership over its life — see fleet management for the same question applied to vehicles.