I'm going to give you a practice consultants view on this. Even though I do manage my sisters practice, I'm growing my consultancy.
Leslie hit alot of it right on the head. But after 20 years, she wouldn't still be in practice if she didn't.
Now, you're going to sense when you NEED to hire someone, because things won't be working quite right. In fact, it will be darn stressful. The trick is to anticipate this in advance, plan your growth and hire for the anticipated manpower needs.
As Leslie said, you want people that can work in different roles as needed, even if one particular task is their primary duty.
Keep that payroll as small as is practicle. But its better to pay a really capable person a little more than to pay a marginal person a lot less. That capable person will pay off in spades. We finally have a kick-[censored] MA and she is worth her weight in gold. I remember when I hired her. She had gone to one of these MA programs and was working as a receptionist for a chiropracter. She wanted something more clinically based. I interviewed her for 15 minutes, excused myself, and came back 10 minutes later and gave her a verbal offer. And offered more than we had planned because we couldn't afford another--I don't want to say it. But you know what I mean. Anyway, Dr. Coghill returned from her trip and I said "Meet Aneka, our new MA."
Use technology to automate anything you can. Get the lab interface for AC. Try out IMH. If it doesn't work for you, stop using it. But its good to see if you can use it to streamline operations, especially if you have a website.
I am a big believer in outsourcing. Peter Drucker coined a phrase that businesses should "stick to the knitting." Do what you do best, and let others do the rest. This includes billing. (a round of "boooo" is heard.) But you must be very careful about an outside biller. Very very careful. It seems that it is better for small practices to go with a small biller and have a close personal relationship with that person. And keep tabs on them. But if you can't find a reliable outside biller, then you have no choice but to bring it in house.
If you have a decent MA program near, you can try out some MA interns. Cycle through them till you get one that is really good, then hire that one! WARNING WILL ROBINSON! YOU WILL GO THROUGH A LOT OF BAD EGGS TO FIND THE GOLDEN CHILD. Make sure the program puts them through their paces. If you draw blood in the office, the MA program should require the students to complete 15 successful blood draws to pass the class. (25 is better). If its only five--leave that school alone! And remember, the intern is not there just as free help--they are there to learn. Take time to teach them what you need. The first two weeks they will be more hindrance than help. But after that, they are actually contributing and happy to do it (well, the good ones are. )This coincides with Leslie's statement about not being afraid to hire someone w/o experience.
You know, that crosstraining thing is REALLY important. I'd recommend that your receptionist be a medical assisant that perhaps is more geared toward (or just is competent in) administrative tasks as opposed to clinical. They will better understand how to schedule patients. And they can go take vital signs and do an EKG too. This will free up your LPN to do other higher-level tasks (when your volume get up).
As far as hours, I'd only say to have at least one day where you are open early(8 AM) and one when you are open late (6 or 6:30 last appointment. Maybe later). Otherwise, it depends on your specific practice and what you want to do. If you are an FP or Ped, you might want to have at LEAST 1 Sat a month. Internist seeing adult only. May not need the Saturday (not in NY, anyway).Depends on the clientele.
I could keep going, but I'm hungry.