Do you know what kind of stain is on there now? That will dictate the type of maintenance that you do, along with frequency.
You are correct that the south side is going to need maintenance more often. If the fading isn't too bad, you should be able to get away with a maintenance coat for now. If there's no bare wood but the fading is extensive enough that it's too noticeable, you can do a maintenance coat of stain and clear coat on that side. If there's any gray or yellow wood indicating severe UV damage, you may need to do some spot prep and blending for maintenance. Feel free to email pictures directly to me at firstname.lastname@example.org. I will take a look and give you more specific advice.
I hope that helps a bit for now. I'll watch for those photos so we can continue the conversation.
Have a great day!
--- Charis w/ Sashco - www.sashco.com - email@example.com
Hi, Billy. I just emailed you back. Sorry for the delay! Been out of the office and not able to check email or surf the net. Let me know if you have any other questions.