In short, the Way to Wealth, if you desire it, is as plain as the Way to Market. It depends chiefly on two Words, Industry and Frugality; i.e. Waste neither Time nor Money, but make the best Use of both. He that gets all he can honestly, and saves all he gets (necessary Expences excepted) will certainly become Rich.
Franklin reduces his practical advice about acquiring wealth to two principles: industry and frugality. Industry means using time productively to earn as much as one honestly can, while frugality means avoiding unnecessary expenditure and preserving part of those earnings. His reference to necessary expenses makes clear that saving is not presented as refusing all spending, but as distinguishing essential costs from avoidable waste.
The claim that such habits will “certainly” make someone rich is characteristic of the maxim’s emphatic style rather than a reliable economic rule. Income, opportunity, illness, dependants and wider economic conditions can all affect a person’s ability to accumulate wealth. Franklin’s broader argument is that sustained work, careful use of time and spending below one’s means can strengthen financial security and improve the prospects of building wealth over time.