The most common problem with kitchen knives is that they are blunt, and the second most common is that people buy more of them rather than sharpening the ones they have.
What sharpness is
The edge is where two ground surfaces meet, and sharpness is how narrow that meeting is.
A dull edge is one where the apex has rounded, either through wear or through damage.
Which means sharpening removes material to re-form the apex, and honing realigns an edge that has bent rather than worn.
The two are different operations frequently confused, and a honing steel does not sharpen.
Why blunt knives are dangerous
A sharp knife cuts where it is placed. A blunt one requires force and slips.
Which is why the injury pattern with blunt knives is worse, and it is the practical argument for maintenance beyond the quality of the result.
Steel
Harder steel holds an edge longer and is more brittle, chipping rather than bending.
Softer steel dulls faster and is easier to sharpen and more forgiving of misuse.
Which is the trade behind the general difference between Japanese and European knives, though both traditions produce a range.
Stainless steel resists corrosion. Carbon steel takes a finer edge, discolours and requires drying immediately.
None of this matters if the knife is never sharpened, which is why steel discussions are largely beside the point for most households.
Geometry
The angle of the grind determines how the knife performs.
A narrower angle cuts more easily and is more fragile.
A wider angle is more durable and requires more force.
Which is why a knife for delicate work is ground differently from one for heavy tasks, and why using a fine-edged knife on bones destroys it.
What is actually needed
A chef's knife for most tasks.
A paring knife for small work in the hand.
A serrated knife for bread and for anything with a tough skin and soft interior.
That covers essentially everything a home kitchen does, and the block of fifteen knives sold as a set contains twelve that will never be used.
Sharpening
Whetstones give the most control and require learning.
Pull-through sharpeners are convenient and remove material aggressively and inconsistently, which shortens the knife's life.
Professional sharpening services exist and are inexpensive, and using one twice a year is entirely reasonable for anyone who does not want to learn.
The test is whether the knife cuts paper cleanly, which takes two seconds and is more informative than any amount of inspection.
The board
Affects edge retention more than most people realise.
Wood and soft plastic are forgiving. Glass, stone and ceramic destroy edges immediately.
Which means an expensive knife used on a glass board is worse than a cheap one used on wood.
Care
Hand washing and immediate drying, since dishwashers damage edges through contact and expose steel to prolonged moisture and heat.
Storage where the edge does not contact other metal — a block, a magnetic strip or blade guards.
And not using the blade to scrape the board, which rolls the edge and is the most common daily damage.
None of this is expensive, and together it makes a modest knife perform better than an expensive neglected one.
Technique
Grip affects control more than the knife does.
Pinching the blade between thumb and forefinger, forward of the handle, gives considerably more control than gripping the handle alone.
Which is the single change that improves most people's cutting immediately.
The guiding hand curls the fingertips under, using the knuckles as a guide against the blade, which is both safer and more accurate.
The cutting motion
Most cutting is a forward or backward slice rather than a downward chop.
Which uses the length of the blade and requires less force, and it is why a long blade cuts more easily than a short one for the same task.
Pressing straight down crushes rather than cuts, which is what damages soft ingredients.
Buying
Holding the knife matters more than the specification, since balance and handle shape vary and preferences differ.
Which means buying in person, where possible, produces better outcomes than buying on review.
Mid-range knives from established makers are entirely adequate, and the returns above that level are small relative to the cost.
Specialised knives worth having
A boning knife if you break down whole birds or joints regularly.
A long slicing knife for large roasts.
Neither is necessary and both make specific tasks considerably easier for anyone who does them often.
Scissors
Kitchen shears handle a range of tasks faster than a knife, including breaking down poultry, and they are consistently underused.
Sharpening frequency
Little and often works better than occasional heavy sharpening, since maintaining an edge removes less material than restoring one.
Honing before each use and sharpening when honing stops working is the practical rhythm.