What do you mean by "[not] regularly"? Do you eat fortified food instead? If you don’t like the daily intake have you considered the weekly and two-weeks intake ?
Everybody make his own choice so I won’t tell you what to do and as you’re vegan since a long time you already know the danger of B12 deficiency but just in case here’s some documentation. Test for MMA, not B12 (it’s far more reliable).
https://www.vegansociety.com/resources/nutrition-and-health/...