I think the rule that we have is that we can transfer the days as long as we have attempted to take them. If we've tried to take them and the time has been denied, then they get transferred to the following year, but if we've just not taken them I'm just letting them sit there, then we either have to take them quickly at the end of the year or get paid the days.
the employer is forced by law to force you to take your vacation days.
Only the minimum required by law though. For example, 30 vacation days are pretty standard in Germany but the required minimum for a 5 day work week are 20 days.
The employee must take those days off whether they want to or not. In extreme cases this could get them fired even.
In Australia they accrue, and I have mixed feelings about that. It's good in the sense that you can do like the OP and save up for like a 3 month vacation, on the other hand, you'll end up overworking yourself before you get there.
However, some (all?) states give the employer the right to force you to use them if you build up too many days.
Source: had to deal with a guy on a team I inherited that had built up a bank of 63 weeks (annual plus long service). He did not want to be forced to take them. He politely reminded him that by law they can, so we worked out a payment plan where he took 3 months off a year to catch up. He will celebrate 40 years at the company in a few months.
Not to be a Debbie Downer about it, but I'd honestly be bricking it that the company goes bust in the interim, and that accruement would be for fuck all.
Same in the UK. I ended up taking basically all of November off because I had hardly any holidays last year. It wasn't intentional at all it just ended up like that.
It's not really worth it because who wants to be off in November, it's cold and there's nothing to do.
Sweden has a mixed system. Generally you are required to use 20 of your legally mandated minimum of 25 vacation days, and you may save the rest. The days can then be saved for 5 years, after which they must be used or paid out.
In Russia they don't, but you have to take at least 14 days off(minimal vacation length) each 2 years. 1 year of work gives you 28 days of vacation. Vacation days never expire. So each 2 years you can accumulate 42 days(6 weeks) of vacation.
EDIT: After more in-depth reading, I'm not so sure if you can get more than 56 days of vacation or get thrown into vacation.