Continual and continuous can’t be used interchangeably. While some people consistently use continuous, other people consistently use continual. For the most part, it’s because they don’t realize that there is another similar word to use, or they have forgotten that it exists.
Let’s examine the difference:
Continual means to repeat frequently, often in succession.
Continuous means to occur without interruption.
Remember that this difference applies to continually and continuously as well. Here are some examples:
The continual showers during the week delayed the office picnic. (The rain would begin, then end, then begin again…)
The continuous flow of information has been a great help. (The information came all at once without any interruption.)
Here are a few more samples:
His colleague’s continuous finger tapping drove him nuts.
The continual repairs at street level were distracting to the office staff.
The phone rang continually throughout the day.
She cried continuously after hearing she would be laid off.
Keep in mind that if you use the wrong word, you may be giving the wrong message to your reader.