It's not exactly the same, but a lot of owners of weird TLDs have got hit with insane renewal fees,.hosting went from $20/y to $300/y overnight.

Also, some TLDs directly speculate on having very low prices for the first year or two, then 10x it on year 2 or 3.

Buy all 10 years you can when you get the domain. Renew yearly. When they pull silliness like this you have at least 9 years to migrate.