I dps as much as I'm comfortable doing. If I'm not comfortable, I don't dps much/at all. If it's something like Wanderer's Palace normal? Yeah I'll CS and dps it down and occasionally throw out some heals because even on high level roulette it's easy now. Depending on the run though, I'll do minimum dps if it's something like the first three dungeons and the tank is GLD (not bagging on them, but Flash spam at that level is not very effective) and I don't have much beyond Cure and Protect to save someone should something go wrong (no Divine Seal or Bene.)

It's not being lazy, it's about how comfortable the healer is, if the tank/dps are taking a crapload of damage, if they're lagging badly that day, etc.