My uses for a pistol mostly fall into EDC, competition, training and field use. While I have more than three Glock pistols, if I had to, I think I could cover all my needs with three red dot Glock pistols:
A Gen 5 17 MOS with a SRO and a CHPWS V4 defender plate.
A Gen 5 19 MOS with an Acro, a Tango Down Acro MOS plate and Ameriglo BUIS.
A Gen 5 45 direct milled for the RMR/SRO/Holosun footprint, one or more optics from that footprint group, and Ameriglo BUIS.
The 17 would be my USPSA Carry Optics pistol, the 19 would be my EDC, and the 45 would be primary for field use and back up to the 17 and 19.
Done.