The purpose of intermediate verbs?

[AlexisLinguist]

The awesome Tips & Notes didn't continue here (yet), so I was wondering what the purpose of I.Vs are? When would you use them instead of the infinitive form, and are they strictly optional or definitely necessary in situations? Also, are there any patterns to them besides leaving off the present tense "-r" for some verbs? Tusen takk!

[Luke_5.1991]

"Intermediate Verbs" is a collection of useful verbs we couldn't find a home for anywhere else. Think of it as Foster's Home for Imaginary Friends but for verbs of all varieties.

[AlexisLinguist]

Ah, okay, thanks!