Most recordings you own by a single artist, group, or composer

Claudia Muzio, Ponselle, Caruso, Gigli, Battistini, etc. opera singers
Rachmaninoff, Hofmann, Pennario, Lewenthal etc. for pianists
Heifetz, Milstein, Rabin, Hassid, etc. for violinists
Segovia for guitar, Zabaleta, Laskine, etc. for harp
Bing Crosby pre-1935 (all on 12 LPs in chronological order), Ruth Etting, Bessie Smith, etc. for pop vocalists
Rosenblatt, Oysher, Peerce, Tucker, etc. for cantors
Django Reinhart, Bob Wilber, Barney Kessel, Shelley Manne, etc. jazz
I have many collections of entire recorded output of many musicians in my 42,000 LP/78/CD collection. I’m pretty sure my list is unlike most collectors/listeners on this forum.

P.S. I am 64 and have many years of collecting.  I also have a normal life, career and family.  I have other interests as well.  I moved last year to a large home which enabled me to house my collection as well as 3500+ books.  If I were starting out collecting today, I would concentrate on CDs and select LPs, particularly those unavailable on CD.  Unless you want to make a commitment to 78s, I wouldn't start.  It is a heavy and delicate collection.  I have many 1000 LPs and 78s which will never be made into CDs or streamed.   As to buying entire output of performers, there are some great sources for 78s, including Marston records for classical vocal and piano, Romophone (defunct) for classical vocal, Biddulph (almost gone) for classical strings, etc.  As to bargain basement Jazz collections, RealGone Jazz is a hit and miss proposition as they don't use masters but often dub from LPs.  AVID collections are much more consistent.  I'm buying more Jazz on CD than any other category.  Great sounding complete sets are being issued by Sony (RCA, Columbia, Philips classical), many good sets on Warner (EMI, Parlaphone & Erato).  Some DGG sets and Decca sets sound good but I find that Decca opera CDs are inferior to the LPs.  

My parents started buying records for me at 2 before I spoke.  By 5, I had 300 records (classical, childrens and 50s R&R).  Through the years, I purchased from stores and collections.  One ethnic collection of unused 78s was purchased from a store going out of business for 50¢ each, about 400.  The last collection I picked through I purchased about 800 LPs from the late Tom Null collection (200,000+) last year.  He was the owner/producer of Varese Sarabande and Newport Classics.  I could have purchased the entire collection very very cheaply, but I did not want or could store that many LPs (and tapes).  

I only occasionally purchase more LPs now and 78s are only from local garage sales.   I have 2000 unplayed classical 78s from the 30's & 40's for sale for 20 years at $1000 but no one is interested.  Tough sell except on ebay for much higher prices but I have no time for ebay sales of 78s.

I purchase CDs on line all the time (7,000+).  I rarely buy a dud.  My friends are remastering engineers and give me hints on great jazz recordings.  My classical and pop recordings are chosen based on reviews or my knowledge of the recording, mastering engineer or producer.  E.G. I know that any Bones Howe early stereo recording is going to be great sounding.   

I only keep recordings if I would want to hear them three times annually;  otherwise, I sell it (or attempt to).  I've sold 18,000 78s and LPs in the past 20 years.   It's my own rule.  

I listen to music at least 1.5 to 2 hours at night, more on weekends.  All through school, I would study with instrumental music in the background (vocal would interrupt my concentration).  My audio systems are so involving, that I eagerly anticipate hearing music daily.  I also perform and record high quality local musicians (occasionally at the Gindi, Disney, Royce, Ford halls and chamber music).

The biggest collections I missed (and couldn’t have stored anyway) were Tom Chandler with 1.5 million, Music Man Murray with 1 million (both collections purchased by the Brasillian collector Zero Freitas ( https://thevinylfactory.com/features/inside-the-worlds-biggest-record-collection-an-interview-with-zero-freitas/) and Michael Lane with 250,000 mint condition classical 78s. I live in the Los Angeles area and have had access to garage sales and collections over the years. I stopped looking for at least a decade and built up my CD collection because they now sound like great analog (especially the Living Presence, Living Stereo and Jazz CDs I’ve purchased). I don’t read books as much as periodicals such as Films of the Golden Age, Chocolatier in Desserts, Moment, Fortune, Westways, Smithsonian, Absolute Sound and Stereophile as well as two daily and one weekly paper. I also still work about 25-30 hours weekly, do the shopping, financials, etc. The LPs worth $50+ in the Tom Null collection were pre-purchased by a local rare record dealer in a package deal although I still found some which he didn’t know about among the 200,000 remaining.  I read that Freitas now has at least 8.5 million records.