My endocrinologist says:

The Reclast medication likely lasts for about 2 years. If you did a partial dose (which is indicated in some conditions), the soonest you would be able to get another dose that is covered by insurance would be 1 year. The partial dosing you’ve read about has likely been done only in studies that have funding to support that kind of protocol.

Partial dosing is likely very effective though I don’t believe there are actual head to head trials on this. Less medication means the effects would likely wear off sooner