Direct to, radial in distance

[CaptainMongo]

Some situations call for extending a fix or the runway. (Direct to, radial in)

How far does the extension extend? 20, 30, 49, 53.5 NM, or to perpetuity?

To much time on my hands, looking for an answer.

[Starbear]

Infinity or actually about 400nm, I seem to recall on one type. Too little time on my hands to research but sufficient to reply in tis instance.