Working on UI design for SaaS,
the biggest issues you will face revolve around adding new features and figuring out which ones should be kept and which ones should be removed.
Firstly, consider whether these changes are going to bring value to your customers, make your content enjoyable, and not complicate the navigation. Always keep in mind the goal of your design: do the new features contribute to it?
Secondly, apart from thinking about customer experience, be sure not to overload yourself and your coworkers. Does this new addition make the management more confusing or maintenance more complex? Make sure to keep the ratio between the added value to the SaaS app UI design and its workload.
And finally, assess the feature and decide if it's necessary or if it can be replaced with a simpler one or just with an existing service.
Don't obsess about creating perfection — your solution should be workable and useful. Regardless of how perfect your SaaS-based application UX design looks like, it still might be confusing. Take a look at Calendly
– a simplistic yet clear design with nothing in excess.