Yes Brother, all the preventive / periodic maintenance schedule is given in the user manual and it covers almost everything.
And you are right. Yei baat main keh raha tha k 3s dealerships are a rip OFF! They treat general public as if; ya to sub karobaari hazra'at hain k khulla paisa hai, ya phir, sub ki haram ki qamai hai!
Spark plugs aaraam sey 60-80k kms nikal jatay hain (even more than that) and maintenance free, high quality, premium plugs even last 1-2 lac kms. 25k kms p to bike k b plugs kharab / replace nai hotay, ye to phir Toyota Corolla hai. Agar 3s dealerships 25-40k kms k baad hi, fazuul aur khwaam khwaa hi mein plugs replace kar daitay hain, then unki zehni halat k liay dua hi ki ja sakti hai.