The bottom of my classic flap has begun to sag. Is this normal? How do I avoid it getting worse?
A base shaper will help. Coincidentally, I just emailed this store to ask whether they have the base shapers for Chanel's classic flaps.
Yes, it's normal. It can be mitigated with a base shaper and/or bag insert.
Here's a recent thread, where I posted helpful, related links:
Base Shapers (for Chanel)...Do you use them & where do you buy?
Ok, great. I will have a look.