I index everything. (I really am having a hard time writing about this because it is so OCD) I have been more or less zoo-ing for 45 years and until I was around 25 this was a rather obscure thing to do or rather, something one mostly did not do (I am 51 as of now). So I wrote journals, kept each and every article, booklet, zoo guide, entry ticket with notes and for most of the time until 2006 any occasional picture I took - and it was all a random mish-mash paper pile until I started to sort it all and basically e-bay-buy additional literature on what I journaled to have seen. Now - as in as of 2006 when I actually caved to the trend to have a digital camera (just kidding, I love it) - I just index pictures by date/zoo and my additional journal (I never did give up on that and on the obsessive collecting of every pice of paper/ticket/souvenir etc. and writing about my impressions) that would indicate what was the most important or the newest/rarest I have encountered that day. I index as follows year/month/day/zoo/outstanding (example: 2018031-duisburg_wombatoffspring_p73). I did rethink this because I am now in 67 journals and 6 TB of pictures all indexed and it is just not accessible anymore - i just could not find **** anymore - it ended to be a meta-index (or three for that matter) by country, species and (believe it or not) season. The index is an excel sheet and I can actually select on all three variables and any cross reference thereof by journal pages. And since 02/2018 once a month I clear 7 zoo days of definitely blurry no good definitely to be deleted pictures. Painful job but I should be done 'anytime soon'.
When I am taking photos I normally go through them at the end of the day, and delete the poor ones,(most of them).
For what it's worth, I store everything on a NAS device with a Synology Hybrid RAID array of five disks and back them up to AWS Cloud. Images are filed by location and date, then keyword and attribute catalogued in Adobe Lightroom. I'm using [checks] 5.97TB of storage, but then, I only shoot RAW and on avarage one 5Ds file is something in the region of 75MB and an uncompressed α7RIII file 85MB. Thank goodness storage is inexpensive these days!
I store my data on 3 external harddisks with the same content, of which 1 is at my parents home to avoid loss of data due to fire or a break in. I index the photo's by data year-month(in numbers to keep the list in cronological order)-day. And I make a short description, like "Port Lympne" or "snow" or "country fair". I always get rid of around 65-75% of the photos taken. And of the ones left I make a very small selection (normally max 5) which I optimize thru Lightroom/Photoshop. Only those selected photos I copy and rename them (with still also the original photoname in the name to make finding originals back easier) and put them in a seperate "favorites" folder. That folder I also have on my laptop.
I have started to backup my photos on google drive and i can the access my photos with my phone or computer. Will soon run out of space though.