If you're just figuring out chords or note combinations then you don't necessarily need to use one all the time. They're good for training you to keep beat with the music as well as increasing your speed.

You might think about getting a drum machine instead of a metronome too.
You can get a much better feel for actually playing to music if you can hear a proper drum beat. Plus you can work on rhythm techniques and different timings.

If you've got the technical knowledge, move into using MIDI files or get something like Band-In-A-Box so you can also practice key changes and different styles of music.