This is my opinion only... I think when we hit 150 million vaccinations (150 million with at least 1 dose), then pull mandatory restrictions and make any mask wearing / social distancing / etc optional to the discretion of the individual. Currently we have vaxed about 65 M and are vaxing at about 1.5 M per day and that should ramp up to 2 M in another week or 2. We should be close to 150 M by mid April if things go well
I agree with the general concept, though I think it needs to be more targeted towards % of at-risk people as opposed to X overall number of people. 55+ make up 93% of the deaths, but there's only ~94M in that age group. If you expand that down to 45 and older, which makes up 97%+ of deaths, there's still only ~135 million people.