To be honest, I levelled my toon from lvl 1 to lvl 50 with only wearing lvl 4 gear, I didn't die as much as youd expect (few times cause wasn't paying attention) and did rather well. The gear does scale with you, an iron sword that deals 20 damage will deal over 1k because its scaled. Its not the most optimal gear, the optimal thing would be constantly changing to reach higher DPS but you didn't ask for optimal, you asked for efficiency, so yes, you can use lvl 1 gear till lvl 50