Following best practices and not reusing addresses has an associated cost.
This and HD wallets are somewhat different issues. The regular non-HD wallets offer multiple addresses in the same wallet too. You just hit create new address, which also creates a corresponding private key in your wallet.dat.
HD or Hierarchical Deterministic means that any address and corresponding private key can be restored from the same initial seed, so if you have that seed safely written down/stored away... you can create new addresses and keys at will, they will all be available to you as long as you have the seed.
With Non-HD, like Classic or Core, any addresses you created after you backed up your wallet.dat... wouldn't have their keys saved in your formerly backed up wallet.dat. You'd need to backup the wallet.dat again to have redundant access to the keys for the new addresses.
I just didn't know they were costing you extra behind the scenes. It makes sense, just never really considered it.
I heard if the transaction isn't confirmed in 72 hours it's dropped from the mempool now. Was this protocol-wide? Or are some wallets doing their own thing in this respect?
https://twitter.com/jgarzik/status/656853984511172609