What do's and don'ts on a ring network

Hey everybody,

Lately I've been struggling with a ring network made up of 9 switches. Switch sitting at the NOC is root bridge with priority 0 and everybody else is at 32xxx.

It's been up for two years and was working great until the last couple of months when suddenly all CPU spike to full and until and unless switches are restarted, there is no getting into them.

There are clients on both access ports and trunk ports and all switches are layer 2. Uplink ports are just trunks and two ports around the network are on alt blk (the ring is a figure 8).

Now I am me but what would be some of the things you would configure on uplink ports and client facing ports? Loop guard and Mac access lists are set on all client facing ports. Most clients connect to routers and some connect to their switch and then to router (because they have multiple upstream and port limitation on router).

Rstp runs on all the switches.

Thanks in advance.