Most phones default to the multi-tap mode.
For typing text messages, T9 Text Input is nearly twice as fast as multi-tap. If your phone has T9 Text Input, on most phones you also can save your screen name and password in the T9 Text Input dictionary for quicker re-entry. Type the name using multi-tap, then switch back to T9 Text Input mode. Don't be afraid to experiment. If successive letters employ the same key, pause a moment or two until the cursor moves to the right.