Events can span between historical or imaginary battles, law enforcement-style CQC engagements, or freestyle urban/jungle warfare-themed light infantry skirmishes. Large events usually have rigid requirements for entry, and can last several days without leaving the playfield. The experience often includes camping, food preparation, transportation, and other military logistics. MilSim differs from the sports of airsoft or paintball - though all rely on tactics and marksmanship, MilSim has a focus on authenticity to real-world military doctrines. There are often fireteams with designated roles, such as simulated combat medics and support gunners.