Dangerous, someone could take over the account from another user. The account may have been used for registrations on other websites and could therefore gain access.

iforget my username. what i do now

The point was to recycle user names that had not been used much. If someone wants to protect their former user names then they should pay the subscription. If someone signs up for a free account and the abandons it, why not let those of us that pay a fee, have the opportunity to get a preferred user name. Maybe a waiting list could be an option.

I would like a previous username I deleted long time ago to be restored so I can use it again.
Right now the support tell me that a username that has been deleted cannot be used again, forever .....
That's not reasonable.
Please make it possible to restore previously deleted usernames.

So because a bunch of lazy pricks can't be bothered to tie up lose ends when they shut down/delete an email account, we have to resort to using names like john.f_cking_malkovich498204@protonmail.com.

And to the person suggesting everyone just purchase a private domain.... Yeah, because you're really gonna get the same bloody quality as with a managed email provider, aren't you.

I noticed that's what you must be doing... otherwise you'd be concerned about protonmail recycling email accounts.... oh wait.............

Too dangerous...

Impersonation

ProtonMail should have the option when you are going to delete an account of free/liberate the username

Bad idea. And there was already a topic asking NOT to reuse adresses:
https://protonmail.uservoice.com/forums/284483-feedback/suggestions/8482354-removing-accounts-after-some-time-of-inactivity-an#comments

just use a private domain for your mails if you have problems with usernames. makes life way easier and doesn't cost that much. (+you don't have to change your adresses when switching the mailprovider) ;)

Please don't implement this idea. The point of this service is secure email and private communications any reuse of a username is a huge privacy breach that would be opened. I'm a paying customer for the reasons of security and privacy but if something as obvious as usernames being re-released became policy I would not hesitate to move to an alternate provider.

Please do, - I noticed, when creating my account, that Protonmail has become very "Yahoo'd", ie: nary a single available username without resorting to names like ******************************* which, to say the least, does not look very good and is likely to get your emails instantly sent to the Spam folder or blacklisted.