There are some spice powders on our kitchen racks that are very personal, and not just the run-of-the-mill stuff. That’s true for the sambar, Rasam mixes in any home with a kitchen where South Indian food predominates. The trick about making them at home is to get the right mix, texture, colour and flavour every single time! That is tough. 
After decades of buying from the same outlet, I found an alternative in Shobhaa’s Podi and I find it to be a very reliable and consistent product. 
Apart from the well-known lentil preparations, I use the powder to spice up any vegetable! It works like magic and balances the dish perfectly!