The longer and harder you have trained, the more dramatic the muscle memory effect after a lay off.
After 7-8 years lay-off I didn't look like I had ever lifted a weight. But within 3 months the bench was at 75 to 80% of pb and despite a buggered back and a bit of a dependence on prescription analgesics, muscle relaxants and anti-inflammatories, the squats were at nearly 75% of pb in less than 6 months. The use of analgesia and muscle relaxants ceased within year and now I hardly ever need to use anything other than occasional over the counter anti inflammatories.
It's a life long journey and the longer you spend programming your body and consistently lifting well, the better the body will cope with any break from training. And lay offs will happen to most people whether they plan it or not.