Strider 3700,
The traditional guidance, assuming as you surmised larger balances, is to rebalance every 12 - 18 months and/or when your asset allocation goes too far off your "glide path" (usually 5 - 10% removed from your current allocation). For most people, this means selling "winning" funds and purchasing "losing" funds. However, if you can rebalance using your new contributions, that certainly helps as well. Several sources (e.g., Merriman on an older podcast) have argued in favor of using new money contributions for rebalancing since many people find it, psychologically, less painful than selling funds that currently have substantial gains in value.
It sounds like you have an excellent start to your investing career; keep it up!
Karl