A CLEAN BIKE IS A HAPPY BIKE

A clean bike is a happy bike.
There are a few easy things you can do at home to keep your bike pedaling smooth and riding nice.
Your bike picks up all kinds of dirt and debris when you ride, whether you are riding on pavement, gravel, dirt or snow.
Keep the chain clean and lubed, this will enhance the life of your drivetrain and help the shifting to respond as expected.  A clean chain will not wear out your cassette as fast either.
Disc Brakes (hydraulic and cable) – Inspect your brake pads to check wear and if replacement is needed.   You want to avoid hearing metal-on-metal grinding noise when you brake.  Check your brake hoses for wear or if the outer casing has been rubbed through at any spot.  Check to ensure there is no oil on or around the brake calipers or levers.  You should consider rebleeding the system for better braking all around.  How often depends on your riding style.  Talk to you mechanic.  Brake oil or DOT Fluid becomes contaminated due to the movement of the caliper pistons.  
Drivetrain – Check your chain regularly throughout the season and replace when needed.  Use a brush to clean the chain and then re-lube.   Clean the pully wheels of the derailleur for smoother shifting.
Tires and Sealant – Sealant can crust up and become a rubbery latex pancake if the wheel sits to long and sealant does evaporate over time.  Tubeless tires need to be refreshed with new sealant during the season.