Whatever number I'm batting at, I always bat with my instincts. To me that's the best way to play.
It can still depend on the situation your team is in. Are you setting a total or chasing one? If you're in need of quick runs, then score quickly but sensibly. Score freely. No point in going out to an unnecessary big shot, especially at number 5 as you are generally seen as one of the last true batsmen on your team.
In wake of an early collapse, play to steady your teams innings.