Should I buy a round trip ticket if I don't know when I'm going home?

-I'm going from New Jersey to California this winter. I don't know exactly when I'll need to be back, whether it will be three weeks or a month. Do i have to schedule a roundtrip anyway, or is it better to buy one ticket and buy the return later? I'm sure it would be more expensive without buying the round trip though.These days on many airlines a round trip ticket costs no more than two one way tickets. The days of one way tickets costing almost as much as a round trip ticket are ancient history. If you can book your return more than 14 days in advance or even only 7 days you'll save money buying one way tickets. You just need to compare round trip fares with one way fares on the airline you'll be using, or shop around if more than one airline flies that route.
IN THOSE DAYS (WINTER) AIRLINES ARE SO BUSY THAT I SUGGEST YOU TO BUY JUST ONE WAY AND WHEN YOU WILL BE CLEAR OF THE DATE YOU WANT TO COME BACK TRY A CHEAP FARE WITH SPIRIT, JETBLU, SOUTHWEST BECAUSE YOU CAN MAKE IT FROM AN UNKWON AIRPORT IN CAL TO AN UNKNOWN JERSYEY AIRPORT