I do the same thing as Bert.
It has to do in part with staff you can trust, and in part with protocols that you set in place.
For example, Bert's practice of peds is well suited to allow staff to prescribe meds for diaper rash and conjunctivitis. He does this under his supervision, which makes it legal, and he has a protocol in place that under a specific situation his staff will react with a specific reaction.
Another example, my office (FP) is suited well for standing protocols on refills for diabetic meds, anti-hypertensives, diuretics, and the like. In our case, my staff will refill these chronic meds for 90 days with 1 year of refills. Provided the patient has been seen within certain time frame, they get refilled by staff. The well controlled HTN pt needs at least once yearly visit for me to renew meds. The diabetic pt needs every 3 month visits for me to renew meds. The staff knows these different circumstances and refill under my authority.
Our state law does not require that I be the one to personally write the Rx.
This may boil down to your level of comfort. But as a solo FP/sole-proprietorship, it's not possible for me to see all the patients, make all the money, make all the business decisions, fix all the computer issues, AND refill all the meds personally.