I make a large amount of my money from affiliate/ad revenue, and it is way too easy for things to go bad.
If you sell subscriptions you own everything. If you rely on affiliate/ad network you always need someone else to pay you, and if something goes wrong you are just out of your money.
Should I consider moving to a subscription based modal and charging for my service as a way of managing the risk and fluctuations from the ad/affiliate model?
Have you tried removing advts for paid customers? How many signed up?
The site is in sports data/betting data/tips
Offer an ad free paid level for users that don't like ads.
And a premium level ad free with extras/more data/tips for users that want more.
If your site happens to be developed on Laravel checkout https://spark.laravel.com/ for a head start on your SaaS development (if you use stripe or braintree).
I like the ability of having a tiered approach for pricing... I don't think I would ever completely remove the free tier, as my data is incredibly helpful to a lot of people so want to still offer a value resource to all.
Just some better/more advanced stuff for the others that would like more...
Removing ads as a tier is a good idea as well.
I like using the auto-responder emails to push the subscriptions and affiliate links...
Seems to work pretty well.