Recurring income is the best when you set this up deliberately as an affiliate campaign, it can become automated over time and then requires a little effort to maintain.
Recurring income affiliate commissions is a required part of any affiliate marketers strategies. You have the long and short running campaigns that pay you one time, and then you add the residual affiliate programs on top and it's these affiliate programs that you need to help you in tough times.
The very fact that a is automated it becomes a low maintenance income stream that can be archived and just checked on now and again leaving you time to create more recurring income strands that grow over time. You see some of the top affiliate marketers do this with such an expertise that they seem to do it with little effort.
Setting one of these up is an easy to do thing, but first you have to find a good one that you know you can dominate or at least hold your own and earn yourself a piece of the residual income pie, examples of recurring income could be membership sites where the customers have to pay a fee each month or even year, they gladly pay for the information and resources that the membership provides, and if you've referred them, then you earn the set rate of that members fee.
Other Recurring affiliate programs are services that provide a need to the individual, such as web hosting, specific software and online newsletters with monthly product updates, it's just a case of getting the right sorts of people to the right promotions at the right time and frame of mind, that is marketing!
I always like joining an affiliate program and then they take the time out to describe the affiliate earning mathematic numbers, epecially in a recurring income scenario, you see that one member could earn you $10 each month and then they say the magic words "What if" you referred 100 people through your affiliate link and they bought the service, that's $1000 for a month. Then they go on and on doubling and tripling the numbers, but the $1000 has already sold me and I've signed up anyway!