ANY OF THE COMMERCIAL carbide sizing dies will last at least to 300,000 rounds to 500,000 rounds, and sometimes many many more.
On the other hand maybe your 38SPL brass is all but worn out. We use to regularly wear out TC sizing dies at the ammuniiton plant and all---ALL!!!---of that brass was run though those dies lubricated with an intensely high film strength lubricant. Sometimes the TC sizing dies would last a month.