OTOH there are a handful of well maintained cars with sludge prone engines even using "today's" modern SN oils. A little preventative maintenance can certainly help. Opinions vary. I know one thing, there was a recent thread about a Honda engine where the owner used the proper oil and followed the OLM and had a mess inside his engine. There are other stories scattered about this site of similar problems following the OM. Many people find out when its too late that they had an engine prone to sludge or problems related to it. Maybe a dose of MMO or Kreen every 20,000 miles, give or take could reduce or eliminate problems. Not everyone has the luxury or being able to look down the fill hole, or pull a valve cover to see what's going on. YMMV