JetBrains Rider helps you respect the principle of locality: if a field is only assigned and used in a local scope, JetBrains Rider suggests converting the field to a local variable.
First, this transformation will normally reduce memory usage (however, this effect may be minimized by JIT optimization). Second, it will improve readability of your code.
note
This inspection only works for constructors.
Here is an example of a quick-fix suggested by this inspection: