I once was actively shopping at ebay for old parts. I was tinkering with many motherboards and parts then.
I've discarded many parts - either sold or dumped, and now focus on making the old games run on the built machines.
Right now have 4 machines -
1. 486DX2-66 for MS-DOS 6.22 + Win 3.1 (8MB RAM, Diamond Stealth 3D S3 ViRGE DX 4MB, VOODOO 1, SB AWE32 2760, LAPC-I)
2. PII 400MHz for MS-DOS 6.22 + Windows 95, on separate HDDs (128MB RAM, Diamond Viper Riva 128, Diamond Voodoo 2 x2 SLI, SB AWE64 Gold, MPU-401 + MT-32 + SC-55 MKII daisy chained)
3. P4 3.6GHz for Windows 98SE + Win2K/XP (512MB RAM, Geforce Ti 4200, SB Live 5.1 Platinum)
4. And current i7 4970K + GTX 980 Ti with Win10 for latest games.
I think I can cover most of the generation of games now. The 486 can be made to play speed sensitive very old games by disabling the cache, but then, there is also DOSBOX to take care of that in my current main desktop.
So, tinkering with parts have really slowed down, but I still like to exchange the parts and play with them - like swapping the ViRGE with a Millenium II card, checking out the PowerVR card, etc..
I tend to always install DOS in all my retro machines upto PIII. I once installed DOS on a P4 and was using actively, but prefer to use it on a PIII with ISA slots.
Some games are too much hassle to make them run on newer machines.
Since my aim was to make old games run comfortably, and now that I can make this happen, I guess hardware tinkering is not as much as before. And I believe there are certain very compatible parts, that just makes you want to avoid headaches with others....for example S3 Virge or Trio64V+ graphic cards that are known for compatibility (but not necessarily for speed). And once you have setups based on those that just work without problems, you tend to start exploring the games or software on them.
I once have successfully built a machine with
SB16 CT1740 + Yamaha DB50XG,
AWE32 CT2760 + Wave Blaster II,
MPU-401
Edit : In addition to SB Live! 5.1 PCI
All in a single machine.... which was a nightmare configuring them -especially when pointing a game to use certain card or a daughterboard and all the interrupts, I/O ports and config.sys and autoexec.bat crazy stuff.... they work.... after the headaches...
But no more... just keeping them simple