> If you store "spam" in RAM until it gets mined you avoid having to redownload and cryptographically verify the "spam" tx once it gets mined into a block Sure, but in the meantime, your memory is free for uses better than storing and relaying spam. I am reminded of the man who said he wouldn't shave because it just grows back again. That's fine as a personal preference, but the alternative tradeoff makes excellent technical sense: at the cost of downloading a few kilobytes later, you reduce the spam in your mempool and provide miners with a monetary incentive to not make spammy blocks (that incentive being faster block propagation). > I would not agree that disk space is abundant. You can get by with just 300MB RAM for an unfiltered Mempool and don't have to upgrade RAM however many noderunners will soon have to upgrade from a 1TB SSD to a 2TB one which is a cost factor and also implies manual effort and downtime. Interesting use of the phrase "you can get by." You can certainly get by without upgrading your mempool, but you can also get by without upgrading your hard drive, by pruning.