I started to notice gaps after a year as a mild signal. A gap of 5 years was a strong signal and nearly every candidate I talked with had some level of hireability issue beyond the gap. Even a mother that decided to stay home till her kids were in school was going to have a difficult re-entry to the rigid expectations of the working world. After someone had be back in the workforce for a year or two and had some mildly plausible explanation for their 5 year gap, I stopped noting it as a downside. But experience older than about 12 years was often not factored in, so a person with a recent 5 year gap will just have less recent and relevant experience than someone who had worked 12/12 previous years.