I'm really sorry to be off the topic but your doggie is just too sweet. Is he full size or still a pup? How much does he weigh? I a regular shiz tsu too.
Anyways, if you love both your bags and can afford it then I say keep them both. I have to identical bag because I am really anal about getting my bags dirty and when one is looking a bit tired, I may either sell it or use it as a on the errand bag and use the new one just for going out.
These pics were taken when the girls were just pups. Aiko (black) is now 8 months old and weighs 6lbs. She is pretty much full grown now. Suki (white) is now 6 months old and weighs in at 4lbs. They are Imperial Shih-Tzus, so they are smaller than average.