I know a guy who took 1 anadrol a day or 5 years. Once he stopped, his blood test came back fine after 6 months, so it depends on the person & their genetics. Having said that, going on orals for that long a period is silly. if you want to be on gear long term, just stick to an injectable. Less hassle, less sides etc.
You could go on primo, EQ or Durabolin & get much better results.