How do you determine how much to spend on speakers

Personally, it's not the loudspeakers as much as the equipment behind them. I've heard reasonably priced speakers, (4K a pair), THAT I didn't care much for, sound superb with $22K of preamp, mono blocks, and CD player. My own experience proved that. I spent most on speakers, not front end. Consequently, not only did it become frustrating, it was costly.
Front end first, as much as is your budget to do. That is the priority.
Loudspeakers second - and here you can start low and move up with almost a new system each time there after.

The only other point to consider is synergy. Throughout a system, it is important. Details like sensitivity, size, price, resale, cosmetics, (not a high priority but important) should not be discounted.
I like the idea of powering less efficient speakers with big power amps. . . but it's costly. The 22K & 4K system I heard that blew me away was top of the line THOR preamp, blocks, and Shan Lings top CD player, p[utting out 30 wpc into a pair of von Schweigert VR 4JR's. pretty impressive sound came out of those little 2K a copy loudspeakers. (audience & HT wires)

Personally I start with speakers. Whatever does it for me that I can afford.
And then I build a system around them that works as best it can as funds permit.
This way you end up with a good front end that when the time comes to upgrade the speakers, there is little to do to optimise for them, simple as cables, or perhaps an amp, and then move forward.

A "strategy" for progress.....although recently I have been through wholesale changes as everything is getting on a bit in age now. And I've mellowed as I 've got older and priorities do change.

basicly I believe there are two schools of thought, one says put your money into your speakers, and upgrade everything behind them till you are satisfied and then upgrade your speakers and begin again. The other says put it into your amplification then go either to your source or speaker next and keep on going back and forth, cabling included until you can't get it any better and then upgrade your amp. i buy my equipment with the idea of hanging on to them for at least a decade, so it is a splash but it lasts. Hope this helps.

Hi all

For those of you that are curious, I have purchased the following components so far.

Bryston BP-20 preamp
Aragon 2004 MkII
Arcam cd72.
Creek obh-9 i believe (moving magnet forgot the number)

I am currently looking to try some new speakers. Currently using wharfdale e-90s. Right now I have a strong inclination toward the Vandersteen 3A signatures.

Interestingly enough I have made my want into analog and have started to despise the cd-sound. Could by my player so I'm currently looking into either upgrading that or buying a new analog rig. Decisions decisions.

After that, the Power Amp is next.

Re: digital sound. In my experience, a good DAC can do wonders for transforming edgy, flat digital sound towards a more layered, musical, liquid analog-like experience. Like Lush, I use a modified Museatex Data II. It's the real deal. The improvement is dramatic, not subtle, compared to playback from my Sony CDP. If you find one, get it. If it doesn't work for you, you can resell at little to no economic loss. I haven't heard the unmodified version, my comments pertain to the John Wright mods. My cost was $350! Other DACs I listened to are DCS, EMM labs, Lavry, Electrocompaniet, Audio Aero, and some others I forgot.