Right after you feed some homeless or adopt a stray
i think 9 months is enough to heal...
Well the next fool man who puts his tongue on that should provide a new piece kind of saying this is our special spot
If all looks good & feels good, okay, but if in doubt it's better to wait a little longer. :-)
I changed both of mine after 2 months . If you feel comfortable with it and that it's healed then it should be fine now :)