I'd buy for my professional repair lab, that is about 10/20% of my company income but it would be really an overkill for my needs, i'd just like to play around with it.

Do you mean revenue or net income?
I really want the DMM6500, it has been sitting on the cart with a nice probe master kit for few weeks, i could not find yet a valid reason to justify the purchase with myself.
Write down all possible scenarios, indirect benefit is a driving force as well.
If not much use later (aka game over) and it start to collect a dust only, you can sell it.
You would be better be familiar upfront with depreciation and write off accounting methods - what loss (if any), taxes and any complications.
Who knows you might get it for "free" personally once its become "unusable"...

The gadget doesn't lose a lot value and kept in a pristine condition will sell quickly for a right price.
Once done, you can move on and reinvest something else.
Also, out of interest, you can find out how much it will cost to rent rather than buy "to play around with it"
How do you guys manage the budget for buying new equipment?
Most important don't regret later if you have decided go ahead.