Independent variable t - @parameter or @variable?

Specific Domains Modelling & Simulations
1

While creating models in MTK for a system of ODEs, should time t be specified as a @parameter or @variable? I have seen different examples use both ways, and both seem to work. Which is recommended? Any particular reasons?
Thanks.

2

There’s a related topic.
https://github.com/SciML/ModelingToolkit.jl/issues/183