We use GitLab CI and solve this with tags. We have runners allocated with set resources and tagged with a t-shirt size. Developers can then tag their job based

We use GitLab CI and solve this with tags. We have runners allocated with set resources and tagged with a t-shirt size. Developers can then tag their job based on this size. Single threaded jobs (curl-uploading a file) can be tagged "small" to get 1 CPU core. Building projects can be medium or large based on how big they are and developers can choose whether the large runner is needed. Because its simple to switch tags, developers can create a feature branch to swap the tag and observe how long it takes. All our runners are self hosted. There are fewer large runners, so developers are inclined to go small. Hypothetically, you can run all your jobs in large but then you may have to wait for availability but in practice we haven't seen any real contention. We run over 15,000 jobs a week on 6 physical servers with this pattern.