As per below statement from Microsoft, don't need to create a cache mechanism to avoid LambdaExpression.Compile() calls.
I will caution you against trying to create any more sophisticated caching mechanisms to increase performance by avoiding unnecessary compile calls. Comparing two arbitrary expression trees to determine if they represent the same algorithm will also be time consuming to execute. You'll likely find that the compute time you save avoiding any extra calls to LambdaExpression.Compile() will be more than consumed by the time executing code that determines of two different expression trees result in the same executable code.
However, still not sure if again and again compiling of an expression tree is memory friendly or not.
Source: https://learn.microsoft.com/en-us/dotnet/csharp/expression-trees-execution
A guy here is claiming that there seems to be no memory problem. I guess we'll see in production :P.
