that would probably depend on how much power it takes to send the messages, how much actual usable bandwidth you could manage over the distances involved, and how much data you want to send.

if it takes a large amount of energy to send the data, we probably wouldn't want to run the equipment all the time. strong pulses would let the equipment cool down or recharge capacitor banks or whatever during downtime.

interstellar dust and other debris floating through space could cause interference, not to mention radiation from everything else around us, and our own sun shining right next to our little laser.

might want to move the laser out onto pluto or something to avoid having it right up against the sun.