1- I am not sure about the indications for weak clutch plate however the declined acceleration is one very common indication.
2- As for timing belt, you do not need to change it before atleast 80,000kms. I changed timing belt of my corolla at 94,000 while my khyber's timing belt at 90,000kms is still doing fine. Dont mess with original parts if they are not required to be changed. Use them as long as recommended. Change of original timing belt at 60,000kms is something i have never heard off.
3- As for brake pads in my case, they were making noises when i applied brakes and grip of the brake had gone bad so i think these are the two indications.
For original parts at reasonable price, contact Kiyani Motors in Gawalmundi. They are a very trust worthy and old dealers of spare parts for suzuki, toyota, honda etc.
For a mechanic, try finding one outside suzuki or vebra workshop. Suzuki/vebra people will rip you off. Suzuki mechanics are not even that well trained as we expect them to be.
CHeers.