I delete gossip memories every play session. I also clear away those fricking "met sim" memories.
By the way,deleted gosslip memories stops auto gosslip interactions between sims till new memory will be generated.No gosslip=no auto gosslip interactions(Yes,I've checked).I never use this option of lotdebugger and not much care if my hood memory data will be bigger for few or few hundreds KB.
For "met sim"memories seems more easier to put "nometsubject" mod in DL.