Best to inspect them every 20,000km. Always use genuine boots as they tend to last a lot longer. No way of stopping their wear and tear. But once you discover it then limit your vehicle usage until you get them replaced.
Also, get a mechanic to properly remove the previous grease and then fill in the new grease. Otherwise, there's a risk of the boot slipping off due to excessive grease. This can cause clunking sounds in your axle cv joint. Most manufacturers sell a complete half axle so that will be a costly repair.
