Recalibrate the vials - that is soooooo 1950s!
If the vials are moveable then the more risk they will go out of true at the slightes knock.
A modern level, with solid block vials and glued in place will not move, and the only time they go out is if the actual level bends.
For my main level, I've had 3 Stabilas in 24 years - the first just got worn out and scratched to bits after 15 years almost daily use on site, the 2nd one bent after being dropped 6 floors, the other, and I'm using the third now for about 6 years - its had many knocks but is still accurate.
About 6 months ago I got a FatMax XL 6' level and it is rock solid, weighs a ton, but guaranteed 0.5mm/m for 10 years.
So get a Stabila, or check out the FatMax range - some are magnetic which is useful for steelwork. Avoid any DIY level - spend £15 on a proper level (not made in China) and it will last you many years