Agree with Josh. While I've been playing for over 35 years and gigged a lot in the 90s, there are some neat things here and there that crop up and surprise you, so it's worth it.
The best way to PRACTICE rhythm playing, outside of having a band, is jamming along to the songs you love, paying close attention to the drums, and how the guitar interacts with them. Working with a metronome and being aware of the important parts of the beat and timing are invaluable for the rhythm player, which really is EVERY guitar player - there is no lead guitar without rhythm guitar.