Halliday & Matthiessen (1999: 216):
The temporal profile, of unbounded/ bounded, is not an independent option available to processes in general. Boundedness is a feature which may accrue to certain classes of process, typically processes of doing: contrast for example unbounded use with bounded use up (use some salt — but don't use it up!). It is on the borderline of lexis and grammar: the verb is extended by up or some other adverb of the locative-directional class (drink up, eat up, load up, pour out, melt down, fly away). The boundedness is not in fact temporally defined; its degree — and often its exact nature — is specific to the kind of process concerned, and may depend on the total figure and on the context; e.g.But there is a clear proportionality involved, which allows us to treat this as a systemic feature of a significant subset of processes in English.
