renewal "higher difficulty" unclear

[Jan69]

it is unclear how renewing a domain works, do you increasingly increase difficulty for every renewal (which makes it eventually impossible)? is it just "more difficult to renew than mine the first time"? what is the difficulty higher of? the only way I can read it, is that every renewal will have to be higher difficulty than the previous one, which I surely hope isn't the case, as it would rather quickly make it unfeasible to renew (if it takes you days, then it's not really worth it)
in case it's merely more difficult than e.g. editing records, but stays the same, then perhaps word it differently, e.g. "renew (more difficult than updating info)" or "renew (takes more time than changing dns records)" or something?