I keep all my solves.
(My csTimer export is literally 5.5 megabytes right now.)
What I do is I have a main session for each event at the top, and then I have a new 3x3 session every week that I do 3x3. Here's a map of my sessions so you can kind of understand where I put everything:
1-17: Main Sessions for WCA Events
18-22: Sessions for Official Competition Solves
23-24: Virtual Cube Sessions
25-26: Former Event Sessions
27: 8x8x8 Cube (Unofficial)
28-34: Other Unofficial Events
35-39: NxNxN Relays
40-41: Mini and Full Guildford
42-43: Rubik's Cube I & II (my main 3x3 session, but divided into 10,000 solves per session)
44: Rubik's Cube Updated (Future) - a session where I'll put some solves I forgot from 2019 in and also provide accurate scrambles for solves I inputted.
45: Rubik's Cube Time Trend (Stats) - a session where I can see a more visible time trend line in the stats function.
46-95: Weekly 3x3 Sessions
96: PLL Drill Session
97-101: Monthly 3x3 Sessions, based on the weekly 3x3 sessions
102-106: Yearly 3x3 Sessions, based on the solves I did that year
107: Cube Buddy Solves (3x3) - a session where I put all my 3x3 solves I've done since September 2020
108: [Redacted]'s Solves - all my sister's Rubik's Cube solves (she's a cuber too!)
109-125: Weekly 2x2 Sessions from September 2020 to May 2021
126: Old Skewb Session
127: ZZ Practice (3x3)
128-140: Subset Practice and Intensive Practice in General (3x3)
141: 8.667 Run (Practice) - a session to speedrun reconstructions of my PB 3x3 single
142-145: Subset Practice on non-3x3 Cubes
145-149: Races Against Other Cubers
150: pbbt - Random 3x3 Solve, I guess? (16.818)
151-155: Old Main Sessions (that were incomplete in some way)
156-179: At-Home Comp Simulations (NOT cubing@home, but independent)
180: -1x-1x-1 Wooooooooooooooooooooooo
181: 1x1 (Rotating to Green-White)
Also, something to note is that my main 3x3 session has 14,469 solves right now.