Others have addressed the process to get paid (legal, factoring, collections etc).
And tinco's comment (currently top) on disengaging emotionally is essential reading. I thought it might be useful to describe what some classes of non or late payer look like from the inside:<p>1) We're solvent, and promised you two week terms - but our accounting dept doesn't work like that.<p>In this case, whoever signed the contract should have flagged that they can't execute two-week terms. But sometimes their eyes have glazed over before they get to that bit of the contract - or they don't know how their accounting dept works (often with a monthly payment run). In this case, the contractor is likely to eventually be paid. But getting paid on the actual terms would only happen if you have enough leverage to get an executive to force the accounting dept to make an exception, and do it every single time.<p>2) We're solvent but have a cash flow problem.<p>Here, a company will push back payments until its cash flow problem is resolved. But that could be months, or even longer. They will make the most critical payments each months - for things that they rely on going forward, like their cloud provider, DNS etc. At this point the engineering team will learn (if they didn't already) to make sure they get notifications of non-payment for critical services, rather than relying on accounting to be able to triage them. Your payment depends on having some kind of leverage - providing a critical service is best, but being the squeaky wheel can also work, as there may be <i>some</i> cash left after the critical ones. Being paid consistently, but always late, is another sign - this means the accounting dept has a hole, but it's of fixed size and they've 'solved' it by taking a float from all their creditors. In this case, you are likely to be paid - eventually.<p>3) We are about to go bust. This looks rather like 2, except that you won't get consistently paid even late, and their other contractors are also likely to not be being paid. If the company is gambling for resurrection, they may even be more engaging on the actual work side, if they think your work is part of what will save their bacon. Legally, incurring debts if you <i>know</i> that you're insolvent is fraud (at least in the UK). But, that hard to prove and only applies if there isn't some chance of not going bust. I suspect that if there's a big chance of going bust, there's actually a propensity to spend more on contractors - since the chances are that they won't need to pay. Sometimes a company structures itself so that it can make a subsidiary insolvent but keep going. This might be identifiable from filings, but I'm not an accountant so I can't advise how. Although, I'm not going to work again for a company where the CEO has made himself a creditor secured against the company IP....<p>Others that I don't have any insight into, perhaps others can comment:<p>4) We are a big company and can get away with X month terms regardless of the contract<p>5) Shenanigans are our way of doing business. We think of it as "playing hardball".