It depends really when in the "Viking Age" you're referring to.

Raids were almost entirely a summer phenomenon, as the weather of the North Sea was far too dangerous for sailing through Autumn and Winter. The raid on Lindisfarne is usually dated to June of 793 for example. Now in the earliest days of Viking raids it isn't entirely clear how the Vikings we're operating. However these raids do seem to have been much smaller on scale with little evidence of raiders staying in England or Scotland for extended periods of time. Many of the first Norse colonies in the North Sea were founded in part as bases for raiders (or traders as the case may be) to stay in during the dangerous winter months.

I cannot really speak to Norse settlement and activity in Ireland or Scotland but this changed in England in rather spectacular style. The infamous "Great Heathen Army" was active across England for a period of years, not months or weeks as is generally assumed earlier attacks were. Robin Fleming's Britain After Rome details a fascinating glimpse into this Scandinavian presence during their stay in one town.

This marked the transition from small raids to flat out attacks on England and the establishment of the Danelaw in England. Until 1066 (and really somewhat later) this was the dominant pattern of Scandinavian activity in England. Large forces that overwintered in England and were active participants in politics, not just showing up to raid some monesteries. This really concludes with the attacks on England by Harald Hardraade of Norway and the later Danish attack. Harald was defeated and killed by Harold Godwinson, and the Danes were either defeated by William the Conqueror or persuaded/forced to retreat depending on the source.

So an early Viking raid would likely have set out in early summer and been active for a few weeks or perhaps months. Then they would either return to Scandinavia or one of the "colonies" established across the North Sea world in order to be sheltered from the worst ravages of winter.They could then either resume raiding in the spring and summer or pick up any other activity that the Norse found themselves involved in such as mercenary service or settlement or even trade. It is simplistic to imply that Norse raids were the only form of economic activity undetaken by the Scandinavians at this time.