Ah--now there's the question. Generally, people prefer "tungsten" darts, which is a heavier material than the more traditional brass. As a result, darts can be thinner providing tighter grouping. Before buying a new set try several different types of darts. Borrow some from your friends or go to dart stores that has a board mounted and will let you try different darts. Once you've tried several darts at a dart shop, it might be considered rude to walk away without buying anything!
There are maximum lengths and weights for darts: maximum length is stated at twelve inches, maximum weight at 52 grams. (Don't ask us why they mix English and metric measurements!) At first, longer darts may be better aerodynamically. Retractable point darts are available from several different manufacturers - many players like them, claiming fewer bounce backs, some players don't, claiming less control. The original and still most popular retractable point darts are manufactured by the Bottleson Dart Company under the name "Hammerhead" because of the way the point moves back into the dart and is hammered off the wire into the dart board by the dart's barrel.
"Generally not. Bounce outs are more a function of the condition of the wires. New boards bounce less than used ones. I've Seen the best bounce game shots using Hammerheads. If your dead on the wire, it is coming out, period.
But they do help keep a good point on the dart. However, don't confuse a good point with being sharp. Stones are meant to remove burrs so it does not pull the fibres from the board when you remove the dart. If the tip is too sharp, it will dig into the wire and you will bounce even more. Remove the burrs, but leave the point with a rounded surface so it will 'roll' to one side or the other when you hit a wire with a glancing blow."