There are some plants like mint that can spread like crazy if you don't maintain it. I had mint spread from my neighbors fence one spring and it just started blanketing my backyard. I had no choice but to use herbicides. Also with age I find it hard to bend down to pull weeds. I mostly resort to string trimmers, some root puller tools and once in the spring some roundup to get me a head start for the year. Longterm I need to add more mulch but I need to fix the yard drainage first since I can't raise the elevation much.