Timers, Modal Operators and Threading

Trigger

Use this skill when the user:

• Wants something to happen later or repeatedly (polling, autosave, a progress readout)
• Runs slow work (network, file processing, a solver) and the UI freezes
• Calls bpy from a threading.Thread and gets crashes or corrupted data
• Writes a modal operator, or one that never stops
• Registers a timer in blender --background and it never runs
• Loses a timer after File → Open or wm.read_homefile

Required inputs

• What runs, how often, and for how long
• Whether it runs headless (--background) or in a windowed Blender
• Whether the work must survive file loads (an add-on service) or belongs to one file