I avoid LRs and LLs if possible and never use them if the wires are larger than #10. As far as the use of the LBDs or oversized LBs, in many cases this is required by the code rules. Conduit bodies are covered by 314.28. If you are using an LB with #4 or larger conductors and the LB is not marked for the maximum number and size of conductors then the LB must comply with the size requirements found in 314.28(A)(2).
