Hi Trish,
I don't blame you for being cautious about getting a infusion of a year's worth of medication since there's no way to remove it if you get side effects. When my doctor first wanted me to get the infusions they were offering me 4 infusions of medication a year so equivalent to 90 days of medication, each time. That sounded better to me. You might ask if your doctor can do this.
I asked asked my doctor at the time why if these bisphosphonates have a half life (some amount of medication stays in your system) of 5-10 years would I need an infusion each yearly. She must basically said that eventually the medication goes out of your system. This answer wasn't good enough for me as I thought maybe I could get an infusion every other year or whatever. You might want to ask your doctor about this, each medication has a listed half life and there all different depending on the medication.