The amount of time in between sharpenings will depend on the complexity and frequency of use. If the knives are used heavily it will need sharpened more frequently. If the knife has trouble cutting through the appropriate item then it will need sharpened. Most knifes in a kitchen where they are used frequently will need sharpened every 2-3 months.
Not too regularly, but it depends on how often you go skiing and whereabouts you ski.
Complete sets often come with 10 or more. However, I would suggest 1 paring knife, 1 serrated knife, 2 sizes of utility knife, 1 butcher knife and a cleaver.
Every day
No how often they will need sharpened will depend on how much you use them and what on.
Changing your kitchen plumbing is not a safety issue. Your pumbing should be changed only if they need it.
You should only sharpen your knives once per year, because after a while of continuous sharpening your knive blade will become thin.
on a regular basis
Normally minimum wage if they are lucky, Kitchen porter jobs should be seen as way into a commercial kitchen, the jobs are unskilled and often dirty, but they give you an insight in the workings of a kitchen.
u speaking of skates? 6 ,months
Because using it produces wear, which makes it become dull.
I personally love to have a kitchen roll holder. I would recommend getting one if you have them often enough.
You should sharpen the knives at least once a year, every 6 months is even better though.