In the days of old (SQL Server 2000) having the auto-update stats setting on could result in large "pauses" in OLTP applications when SQL decided to do a statistics update.
From SQL Server 2005 onwards there is an asynchronous option which will not result in the "pause" when stats are out of date and subsequently recompiled. The stats will be recompiled asynchronously for the next time they are required.
Bear in mind though that there is a balance to be had - for large data sets you may want the current query to take the most up to date statistics into account, since the query may take exponentially longer with an inefficient query plan.
You can also monitor the number of recompiles per second and other crucial performance metrics using the perfmon counters that are published by SQL Server, as they say, the proof is in the pudding.