Split ends can come from many things, such as environmental factors (sun, wind, cold, dry air, swimming in chlorine, hard water, etc.), rough handling, improper protein/moisture balance, use of hair products not designed for your hair type. I suppose a little is inevitable.
It should help if you dust and/or trim several times a year.
I recently found some myself and am thinking of getting a dusting after the first of the year if it doesn't get worse.