Well this is a paper type air filter and there is nothing as a maintenance free airfilter or a life long one until unless ur using something as expensive as a K&Ns air filter!
U must replace this filter when it becomes oily/greasey/dark... No matter how well it is made it should just be used no more than 3-4,000kms.... Personally I would change it at every 2nd or 3rd tuning as a rule.
This is simply a marketing bull-**** by Suzuki guys! They couldn't fit a washable foam type filter in it and they named this one as "maintenance free" 
Bai my Junoon has a paper type filter built into a metal frame and costs 200rs now... But karwana parta ha change wo b? Paper type filter jitna bhi acha ho? 1. It has a limited life 2. It only works best when new and clean 3. It starts to choke ur bike when oily, geeasey/wet... Won't let air pass through it.
Hence yar don't use it for too long, ud just increase ur fuel costs and would have a bad idling bike.
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