Jothar,
I keep the Avraham Greenbaum “sweetest hour” book at my beside and it directs that Tikkun Rochel is “only recited on days when Tachanun is said.” Sometimes I wake up spontaneously during the midnight watch and figure I have nothing better to do than to recite the Tikkun, but this practice is irregular and an infrequent occurrence and not a habit.