Why British imperial strategy acquired and relinquished territory

Why can British imperial history look like a long sequence of acquiring and later giving up strategically useful territories?

Territory was valuable when it protected commerce, extracted resources, or broke a rival trade monopoly; permanent direct rule was not always the most profitable choice.

In this interpretation, British territorial policy served trade and financial gain, with direct administration worthwhile only when it supported those aims. War cost money and interrupted commerce, which gave Britain reasons to avoid conflicts and challenge rival trade monopolies. Resource extraction remained part of the imperial system. Francis Drake and Walter Raleigh provide examples of attempts to trade with Spain's American colonies despite Spanish restrictions, including participation in the slave trade. Colonial customers could welcome outside traders and then describe their visits as raids when Spanish warships arrived.