I have read an article about droping the old and reduntant stats , to keep only the used stats

copied

" This may sound like a radical idea at first, but think about it. What do you have to gain or lose? Dropping all auto stats will place some temporary stress on the system. As queries come in, the query optimizer will begin recreating those statistics that we just dropped. Every query that adheres to a certain pattern that requires a statistics to be created, will wait. Once. Soon, typically in a matter of minutes for highly utilized systems, most of the missing statistics will be already back in place and the temporary stress will be over. But now, only the ones that are really needed by the current workload will be re-created and all the redundant ones just came off the expensive maintenance tab."

" It’s a price you must pay to get better plans which means better performance "

do you have any advise

Thanks lot