I have a 10 week old, my first, and there are times when he's been fussy for like 2 hours straight for different reasons, and I'm finally hitting my limit (it's really high but it is still there) but then he smiles and I'm replenished so I can give him more again! His huge smile melts my heart every time! It's so cool and totally worth it! Watching him learn new things makes other things kinda meek in comparison.