Since there are no Power Berries in Harvest Moon DS you will start with the maximum 100 points of Strength and 100 points of Fatigue. The tools that you use will deplete your Strength until it reaches 0, then the Fatigue begins to count up to 100. Once you have 0 STR and 100 FAT your character will pass out for the rest of the day. If you pass out you will loose half your money! You can see your current STR and FAT values by equipping the Truth Bangle.