There's several schools of thought on this.
I'm of the opinion that if your mains can handle the lows gracefully, it's safe to run them full-range. I do that with my lowly Athena AS-F1's and so far, it's working out great. Music comes out great, as do movies. Strangely enough, for music, the sub rarely comes into play but when it's need, it's there.
I have the receiver's* crossover set to the lowest it can go (80 Hz) and set it for "main+sub"
*Denon 2802