Are pattern parts worth the saving?

Once my 2007 Mazda 3 was out of warranty I switched my servicing to a local and more convenient lower cost multi-franchise garage. Looking into parts costs I was amazed at the difference in price between branded parts and others. For example a Mazda pollen filter was over £50 for what appears to be a very simple low-tech item, compared to £12 from Eurocarparts. To replace front brake pads, my local garage have quoted £100 and the Mazda dealer £150. The Mazda dealer told me that the pads account for £100 of the total cost. What are your views and experience on sourcing alternative parts and do you see any problems in doing so?
If they are the genuine parts merely being sold by the parts manufacturer rather than the car manufacturer via his dealer chain, then that's the way to go. If they are specialised improved parts such as Rossini brake discs and pads then also very good. But if they are 'pattern' parts they can be extremely dangerous. For example, a 'pattern' oil filter can wreck an engine by not having the correct internal valving. A 'pattern' clutch may fall apart. ‘Pattern’ brake pads may disintegrate.
Answered by Honest John on

Ask Honest John