Ability Checks, Advantage & Disadvantage | Game Master Companion 5e

Ability Checks: Advantage and Disadvantage. Here are a number of reasons why advantage or disadvantage would apply to an ability check. There are many others.

Ability Check has Advantage

You work with another on the task
You benefit from a spell
You use a helpful tool
GM discretion
GM grants you inspiration

Ability Check has Disadvantage

Due to environmental conditions
You suffer a debilitating condition
You are encumbered (variant rule)
GM discretion
You lack armor proficiency