The amount of time, or the number of products produced, it takes for the implementation of a new process to have a net gain of $0. Usually there is a lot of up front costs to implement a process and that initial investment should be paid off before the lifetime of the process. If the break-even point is a far way out then there is a lot more uncertainty and that new process option is less desirable.
Example: A new whirly-gig fabricator can be purchased at $50,000. The whirly-gig should be able to add $15,000 in value every year. When is the break-even point?