The investment aspect is shakey at best. Audio equipment has a very low return rate in the best of circumstances. You have to add the intangibles such as the ability to custom tailor the equipment to suit your particular needs and the economic benefit of having the expertise to do your own servicing. Determining the cost benefit by deciding what the DIY stuff is worth in terms of sound quality is also dicey. There are plenty of very good loudspeakers from the past 30 yrs that will perform as good as you could possibly want and are avialable for fair prices. The real trade-offs occur to my mind in the trends that designers follow concurrent with musical styles. As music changes it is recorded in ways that follow the trend. This results in design descisions that compliment those musical styles. The speakers are then built to flatter the music recordings. So buying new eqiupment means you are shaping the sound in those directions. This may mean they are not as suited for other types of music. What you build; you build for the satisfaction. A pair of Snell Type III two ways from ten yrs ago cost 200$ A Fisher or Scott reciver upgraded is 500$ and a Thorens table with a decent cartridge is 250$ Thats 950$ and the sound is 90% as musical as anything you can build or buy. So unfortunately we do this for the personal satisfaction; because lord knows we don't save any money on it.