Flexible pipe broken again! Should all engine mounts be replaced?

Hello fellow enthusiasts,

After a long period of trouble-free operation and almost 20,000 km without any real issues (ball joints, water pump, and a faulty mass airflow sensor shouldn't be a major problem for a real TDI driver, right??), I've encountered a minor issue with my exhaust system.

Brief history:
8/2005: Catalytic converter rattling, monolith loose --> replaced with a new (metal) catalytic converter.
12/2008: Exhaust is very loud (flexible pipe?), and has a red emissions sticker --> PMS (Mangold/Oberland) installed.
1/2012: The exhaust is roaring again (possibly a problem with the flexible pipe)!

'In the middle of last year, I replaced the front left engine mount (due to...)' Oil leak.

Given that the average lifespan of a Flexro hose is approximately 3.2 years (or about 45,000 km), I have a question:

Should you replace all four engine mounts at the same time when replacing a damaged flex pipe?

Or are there only...? B. Are the front, hydraulic bearings more prone to failure?

I'm looking forward to your answers.

BTW: The search results yielded some entries, but nothing relevant regarding [topic]. Relationship between the lifespan of flexible pipes and motor mounts.

Best regards, K. Oldewurtel.