But I think Italy are mostly 90 days (apparently due to that being Fiat's terms, and everyone else followed suit).
In Italy the situation was so bad that it was not uncommon to get 180 days from big accounts. The State set an awful example by allowing 12 months on its own bills, and often wouldn't pay for years if at all (what are you going to do, sue them? The average lawsuit takes more than 2 years...). In the last decade, several acts of Parliament were passed to actually force national and local administrations to settle their bills - and a lot of them were still outstanding a year after that. About two years ago, the government passed a law forcing all businesses and administrations to pay in 30 days by default (with some exceptions, of course). Whether this is actually being enforced, I don't know (I don't live there) but in theory it should allow smaller businesses to be a bit more confident when signing contracts and asking to get paid.
In construction I have seen more often than not the formula (jokingly) "180 days we'll see", meaning that for 6 months there is no way you'll get paid, then we'll see what we can do.
And the Law(s) do little about it (and no, these ones are not usually enforced).
But the issue is not actually the delay (for which - costly BTW - remedies exist) but rather the uncertainty and the time lost.
If we agree that you pay me after 60 or 90 or 180 days (talking of "continuous" work, supplies or services) it's ok, I can make a financial plan taking into account that delay, and include in my offer (at least part of ) the financial costs of that delay.
In the '80's and '90's I worked in a company that had "standard" payments terms for "large" suppliers set at 90 days, but then that actually meant that on the 90th day from the date of the invoice, a payment was made on the supplier bank account, always, sun, wind, rain or snow.
What happens often nowadays is that the agreement is actually 60 days, but after 60 days nothing happens, and so you have to call (and of course you can't ever find the right person) and then call again the day after, then you write an e-mail, then you wait, then you call again, then you write a letter and they tell you to have some patience as everything will be fixed next week, and next week you call again and there is a problem with the "system" (or with the bank's "system"), so you have a lawyer write a legal letter andm finally they pay with the 60 days becoming 90 or 120.
In the meantime you already delivered another supply, rinse and repeat.
”Main provisions of the Directive
Public authorities have to pay for the goods and services that they procure within 30 days or, in very exceptional circumstances, within 60 days.
Enterprises have to pay their invoices within 60 days, unless they expressly agree otherwise and provided it is not grossly unfair.
Automatic entitlement to interest for late payment and €40 minimum as compensation for recovery costs.
Statutory interest of at least 8% above the European Central Bank’s reference rate.
EU countries may continue maintaining or bringing into force laws and regulations which are more favourable to the creditor than the provisions of the Directive.”
I wouldn't have minded if the contract had specified 90 day terms and payment had been timely after that. But the contract said payment would be made "promptly."
Sometimes the only way I'd get a payment was by hassling accounts and senior management day after day after day. It was a huge waste of everyone's time, and - unsurprisingly - I moved on as soon as I could.
UK clients would usually pay promptly on 30 days. Occasionally there were problems at the end of a quarter when VAT bills became due, but they were rare.