For home hobby purposes and cutting cardboard or paper, a 9mm utility knife with a metal body is recommended, such as the Berlingo Razzor 100 or Kangaro Mini PA 901 - lightweight and precise for detailed work.
9mm blades are suitable for precise and light work, while 18mm are stronger and are used for cutting thick materials such as rubber, vinyl, carpet or insulation.
The blade should be replaced as soon as you feel resistance when cutting or serrations. For frequent use, a set of replacement blades size 10 is recommended, which are easy to replace.
For office work where envelopes, paper or cardboard packaging are cut, compact 9mm knives such as Centrum small, OfBox Art or Kangaro metal are suitable.