Just wanna start saying that hope everyone is safe and healthy. I have thought about user testing done for apps sharing the same domain to start the design improvement process. For example I have had 4 clients last year all into retail banking domain with very similar features. I just wanted to hear your thoughts on conducting the user testing each time with the same purposes for each app (purpose is to detect usability problems). Considering the cost of testing (time and budget) I believe with the know-how in hand expert review is also sufficient in this case. I ended up with detecting the same problems I've detected through expert review and feel like I'm just spending unnecessary resources and extending the timeline of the project. What do you think on this matter? How would you communicate it with your client?
It depends on how much the features and users differ per product, and what the risk and impact will be when you don't test. But if an expert review shows that the cost of user testing most likely won't outweigh the cost of possible fixes afterward, it's fair to assume that risk and impact are low. You could communicate past test results, the expert review and an after-sales plan based on a risk, impact and costs analysis.