The easiest way I find to catch up is to click on the 'New Posts' at the top centre of the screen as you will get a list of EVERY post been made in EVERY section since you where last on the Forum. I was just using the bouncing bike icon before that but discovered I was missing other posts in the same section after reading just the one.
If you only log in once in a while though you best grab a coffee & get comfy as it can be 4 days or so between my log in's & it can be a big list!!!