[kahawe]

The sad truth is that there are customers doing that on purpose not just to protect their own liquidity and cash flow but they hope that by not paying and making you wait they will literally dry you out into bankruptcy and ultimately they hope they won't have to pay then.

Government contracts, at least in certain countries here in Euroland, are NOTORIOUS for doing that to small and mid-sized companies. So make sure you always protect your interests, if possible get some money up-front, a part after a significant milestone and the rest upon completion. And ideally work at having a good standing and connection to the instance who can actually sign off on and pay what they owe you.