1) Accustomed to 2) Accustomed with 3) At ease with 4) At home with 5) Certainly experienced with 6) Comfortable with 7) Did in the past 8) Did once 9) Did, at some point 10) Did, but no more 11) Did, once upon a time 12) Experienced with 13) Familiar with 14) Formerly did 15) Fully comfortable with