When installing cabinets, it's important to achieve proper alignment and level, otherwise it can cause issues with the cabinet doors, drawers, and hardware. Tolerances, or allowable deviations from ideal measurements, will vary depending on the manufacturer's guidelines, but in general, the following are considered acceptable tolerances for cabinet installation:
Level: Cabinets should be level both horizontally and vertically. An acceptable tolerance for level installation is within 1/8 inch for every 12 inches of cabinet run.
Plumb: Cabinets should be plumb, which means that they should be perfectly vertical, with no tilt or lean. An acceptable tolerance for plumb installation is within 1/16 inch for every 12 inches of cabinet run.
Square: Cabinets should be square, which means that the corners should form 90-degree angles. An acceptable tolerance for square installation is within 1/16 inch for every 12 inches of cabinet run.
Gap and alignment: Cabinets should be installed with a consistent gap between them and with doors and drawers properly aligned. An acceptable tolerance for gap and alignment is within 1/16 inch.
Hardware alignment: Hardware such as knobs and pulls should be aligned and centered on the doors and drawers. An acceptable tolerance for hardware alignment is within 1/16 inch.
It's important to note that these tolerances may vary depending on the manufacturer, and for some high-end or custom cabinetry the tolerances may be more stringent. It's important to check with the manufacturer for their recommended tolerances. And in any case its recommended to have a professional do the installation to have a good fit and finish.