You can customize characters by giving them equipment and custom moves. (We'll talk about the moves later.) Customized characters can be used in some, but not all, modes. They usually have to be enabled by touching the wrench symbol on the bottom screen at the character select screen.
One way to customize a character is to give them equipment. Equipment can raise or lower attack, defense, or speed, as well as bestow special traits or abilities. Each piece of equipment will raise one stat and lower another, but the amount gained will be more than the amount lost. This way, you can sacrifice one stat to greatly increase another, or wear three pieces of equipment that largely cancel each other out but leave you with small boosts in all three areas.
Equipment can be collected in various modes. They're always marked with a small wrench symbol. Equipment and custom moves look the same before you pick them up. You're more likely to find equipment that can be used by the character you're playing as.
Equipment is semi-randomly generated and can be earned in basically any mode. The most common type of equipment, badges, can be used by anyone. Other types of types of equipment can only be used by specific characters. Swords, for example, are only useable by characters who use swords, and magic gems are only for characters who can use magic.
If a piece of equipment has a special ability, it will be listed next to its stats. Press X to see an explanation of what the ability does. Helpful abilities are printed in black, and harmful ones in red. You might want to equip a piece of equipment with a harmful ability because its stat penalties are lower than other comparable pieces.
Equipment has an effect on the number of Smash Powers you can carry in Smash Run mode. Lower speed means the ability to carry more powers. It's a tradeoff. See the Smash Powers section for more information about Smash Powers.