The tape measure and caliper will help you track your progress as you become leaner and stronger. Especially helpful when the pant size is going down, but the scale may not be (due to muscle development).
Track your fitness with the tape measure and caliper. When improving your fitness and health, the scale, waist size, and body fat percentage should all improve. However, as long as one or two of those factors are improving at any given time, you’re improving your health. Don’t just focus on the scale.