M.J.
I have 2 kids and a husband getting the shots. They seem to make a big difference. My oldest son kept getting sinus infections due to allergies and he hasn't had one in 3 years, since he started the shots.
The way it has worked is that they get them weekly for so many shots, then you go on maintenance where you have to get them every 3 weeks. Then when that serum is used up, you have an appointment for an evaluation about continuing them. Start a new serum, get so many weekly shots, then maintenance.
My biggest complaint is the hours that you can get the shots. This is specific to the place you get the shots, so your situation could be completely different. Their office is not open on weekends and Tuesday nights they are open until 6:30pm. Some days they are only available until 4:30 for shots. They do early ones on Thursdays, at 7 am and we have had to resort to that a few times to fit it in their schedule.
I didn't start the kids until they were older than six. One started at 9 and another at 10. I think it has been worth it.
M.