Hello there, guitar slingers!
The answer to today's question will probably surprise most readers. The most important factor is the guitar playing level you were at before the one-year break happened. Whether you are an absolute beginner or an experienced guitarist, the effect of stopping playing your guitar for one year is going to be different.
If you are at an advanced level, nothing extreme will happen. You can return back to 70–80% of your playing ability within a couple of weeks. Only the really advanced stuff will make it a little difficult for you. After a couple of months or so, you will be at 90–95% of your previous ability. At this point, you will probably not be able to tell the difference from your playing before that one-year break to where you are now.
If you are an intermediate guitar player, you will regress to playing the things that will be very safe for you. Meaning that if you are, for example, a metal guitarist you are not going to be able to perform some advanced guitar solos the way you did before, but on the simpler rock stuff you will do just fine. It will take a few weeks to get back to your playing level. For example, getting your bends in tune again. In about a month you should be at about the level you were before that one-year break. Just be careful and try to not get hurt and develop tendonitis, because this is always a big risk when you are starting again after a long break. Apart from that, it is not a big deal. You should be fine.
If you are a beginner you will regress to being almost a total beginner, again! Apart from forming some simple basic chords, you will have a hard time doing anything else on the guitar. The main difference here is that if it took you six months to get to the level you were at before the break you will be able to reach it now in half or a third of the time. So, it will take you three months to be back to the level you were before the break.
These are things that I have noticed from my 25+ years of guitar teaching experience by watching people getting back after long breaks.
If you want a more thorough and detailed explanation, you can watch the video below, where I explain the subject in more detail. This is part of my "Ask the Guitar Coach" video podcast series, where every week I answer guitar-related questions.
Ioannis Anastassakis is a guitarist from Greece who has produced recordings in a variety of moods and styles, including flamenco and fusion.
His CD is entitled "Suspension Of Disbelief", his long-awaited rock/fusion instrumental album.