What proverb in English means that people get rid of old habits hard? (if there are any)
Depending on the context a leopard can't change its spots may be appropriate.
This proverb means that despite all efforts (or advice), a person will revert back to their old self (habits). It is usually used when referring to bad habits.
This idiom comes from the Old Testament (Jer. 13:23). The Hebrew prophet Jeremiah tries to persuade an evil shepherdess to become good but when he realises that it is impossible to convince her, he says: “Can the Ethiopian change his skin, or the leopard his spots?”
From: bloomsbury international
Another saying that may be relevant is this one, cited in both Rosalind Fergusson, The Facts on File Dictionary of Proverbs (1983) and Wolfgang Mieder, A Dictionary of American Proverbs (1992):
Habits are at first cobwebs, at last cables.
The sense of the expression, of course, is that the longer we do a thing, and the more accustomed to doing it we become, the harder it is for us to give up.