One day I've sent a big transaction of ~5 btc with zero fee and it was confirmed in less than 30 min. Maybe I was lucky or maybe it was the 5 btc I dunno know. Now I put always 0.0001 bitcoin as fee and for me is very fine, it is less than 0,02 $ !
Zero-fee transactions are based on the weight of the transaction, which takes into consideration the input size, output size, and age. If you held 0.1 BTC for a day, you'd already have enough weight to negate the need for fees (if you were sending at least 0.01 BTC). 5 BTC was way overkill for the system.
I like the term "weight" to mean the size in bytes. Generally, the "size" of a transaction is considered to be its value, so a term like "weight", which also implies a burden, is better. I'm going to use it from now on.
Weight is in relation to its importance in the network, NOT its cost. Higher weight = higher priority to be added. I think you're getting terms confused here. In fact, it's the opposite of what you said: higher weight = LESS fees needed, since it's already a high-priority transaction.
I didn't read your post closely enough. I still prefer the "weight" of a transaction to be the size in bytes, even though there still might be some confusion. Is there precedence in using the term weight to me importance of the transaction? Is there a better term that could be used?
Very good question. In the crypto world, verbiage is always being changed. For example, some still count BTCs in bitcoins, while others do it in bits.
Weight is one of those things... but it's pretty common to use the term "stake weight" to determine your power on the network (i.e. chances of staking a block, relative to others), and that's so widespread that I think changing it would only cause more confusion.
I do agree that "size" has an unclear definition, as well. Size could be bytes or it could be coins being sent. It's often used interchangeably and really shouldn't be.
What we need is a solid group of definitions that everyone pulls from.
