But its OK to do if...?
You simply enjoy it.
You like the experimentation.
You occasionally make something that sounds good.
You can cope that you can never get back to that ace patch you did a while back.
You sell other things in your life that you don't use to fund your modular.
You can cope with not buying everything at once.
....and you don't have to be good at something to enjoy it.
Enjoy your spare HP, don't rush to fill every last space, this is not like filling sticker books. Resist the urge to 'complete' your rack, its never complete so just relax.