With more than a year sober, I have many days where I am fine and my thoughts are clear, the obsession isn't there. I think I am past the impulsive thoughts and actions of addiction, but there are definitely days when it is still a struggle, and my thoughts start becoming screwed up.
My own early warning signs are when I begin to neglect self-care, stop sleeping as well, etc. I can even have a return to some of the symptoms of withdrawal I had in my first month of recovery. It can definitely be triggered by stressful events, which are impossible to avoid all of the time. However, I can have some control over how I react and respond.
I try to seek help before the early warning signs develop into full blown relapse mode. In early recovery I was provided with a list of numbers for mental health or addiction services, and I make use of them - that can often return me to more objective thinking.
There are times when I seem to begin sabotaging things in my life so that they go wrong... and ultimately it seems to come back to giving myself an excuse to drink, it is still the case even after this time sober. I have become much more conscious of that over the past year and fortunately can now see a few patterns which will alert me.
My worst struggle was the thought sometimes that 'surely now and then can't hurt that much, it's not going to take over my life again'. I still toy with the idea, but know deep down that a little is not enough for me and never will be. The mental health, social risks etc is not worth it. I still have these thoughts occasionally but they do pass and I get back on track. I have worked hard on accepting the nature of my problem.
Of course, it is up to each individual to search for and work an ongoing course of therapy or program for themselves. I do try to reflect on and assess how I am going in my sobriety regularly, day to day.