I am curious about the tradeoffs of the setup I currently have. My indices are setup as 1 for each month of the year instead of 1 per day. The number of events per day are 100K to 200K depending on user traffic. Just looking for advice on whether it would be better to have daily indices vs monthly.
Here's an article about shard sizing:
TLDR fewer larger shards are better (up to a point of course, but that point is a long way off in your case). Here you could reasonably go for yearly indices. Daily ones would definitely be far too small.