Thanks.
I'm not sure if this is standard for my nationality (as I said, I've only had two passports so far, I got my first one when I turned 19 and another one a couple of months after I turned 24; I left my birth country when I was 19 and haven't lived there in 8 years — so I don't have all that much experience to tell about procedures in other places, even in the country I was born), but in the Consulate that I renewed my passport they state in the biographical pages that that passport is a renewal and a replacement of [number of old passport] and include added information, such as which Consulate renewed it, the name and signature of the Consul, the sum paid (i.e. fees). If I had any legal issues pending (e.g. not having voted, which for us is compulsory and we can only get a temporary passport in order to travel to the country and solve things there, otherwise we're not allowed to renew it fully), it would have been mentioned as well. Since I vote in every elections from here, I clearly don't have that issue and therefore no note attached. Everything is outlined very clearly.
The old one gets stamped in all pages which don't have immigration stamps or visas with the word "Canceled" from one cover to another. My first passport expired at the end of November 2011, and I renewed at the end of January (and it was ready in the beginning of February) 2012. It wasn't much of a gap.
I'll definitely be more careful this time.