Travel Iinquiry to Hong Kong

I'm an Egyption backpacker, i've been traveling in south Asia since 11 month, I'm going to travel In Hong Kong next, My question: Do I have to get a return ticket? I never know how long I stay in a country, I will search mainly for martial art schools, if I wasn't lucky I will fly to another country, the main issue is the length of my stays, that varies and depends on whither if i 've found sth or not. Thank You!