QOAuth2AuthorizationCodeFlow - who is responsible to call refreshAccessToken?

[orio]

Hi,
my first post .

using QOAuth2AuthorizationCodeFlow from code examples that i found all over the net.
using desktop application ,at startup I manually call refreshAccessToken and things are OK.

what I do not understand is who is responsible to the next calls to refreshAccessToken.
assuming that the app will be open for long hours...

never worked with rest / Oauth before , what is the idiomatic way to refresh the tokens?

shouldn't QOAuth2AuthorizationCodeFlow do it for me? (nothing in the source code showing it)
should I setup a timer that will connected to refreshAccessToken slot?
should i wait for failure in api call and then call refreshAccessToken?

thanks.
ori