>>142476
Just do everything consistently. If it gets too easy, then worry about more weight. You're resting between sets and exercises, so you have the time to modify your dumbbell weight between exercises. You're going to have to do that when you start hitting plateaus in certain lifts, so don't worry about what anyone thinks of you.
If you're focusing on strength, then increasing weight is important. More so than reps. If you're increasing endurance, reps are more important. Typically strength is 3-5 sets of up to 5 reps. Endurance is typically 3-5 sets of 15+ repetitions.