In most multiplayer gametypes, you can set the weapons on the map to respawn after a certain amount of time that they are moved from their spawn point. The time it takes for each weapon to respawn is different for each map. For Halo: Combat Evolved, the "basic" weapons (Pistol, Assault rifle, Needler, etc.) mostly spawn every 30 seconds (save Chiron TL-34, on which everything spawns every 45 seconds). The Rocket launcher commonly spawns every 90 seconds, and the Sniper Rifle's spawn depends on the map. The grenades, power-ups (Active Camo and Overshield), and health pack have no set spawn time, meaning that it is random for every map. However, the grenades seem to alternate spawn at either 30 seconds or 180 seconds.
Halo 2 has no uniformity, unlike its predecessor. The most common spawn times for weapons are 15 seconds, 30 seconds, and 45 seconds., along with power weapons, have different spawn times depending on the map. The power weapons follow a special set of rules for spawning. If someone is holding one of the set of power weapons it will not respawn. However, if one of the power weapons is dropped and it contains no ammo, it will disappear instantly, save the sword. Power weapons also disappear and respawn independently of each other, meaning that they run on different respawn timers. The PAL (European) version of Halo: Combat Evolved is slower than the NTSC. For each minute, the PAL version adds 10 seconds.
In Halo 3, smaller weapons spawn somewhat frequently, usually after 20 to 30 seconds each. Power weapons can spawn anywhere from 45 seconds to over a minute. Maulers were set to the former by default, but were put up to 45 in an update. In Forge, a player can set their weapons anywhere, and likewise decide on when it will respawn, and for the first time, if it will respawn. This allows for greater flexibility when it comes to altering maps.