dvd cd

i have purchased desktop dvd writers of many companies . but all of them get useless after a short period of time i.e. 3 to 4 months and i don't use them so much how they get useless they are unable to read the disks i opened them and clean their lens then they works very good for...

asus bw-12b1lt i want to buy this model and dl and single layer blank blu ray and dvd s which supprt lightsurcribe can tell where i get these alll cheapest in delhi or rajsthan or any place in india