I have roughly 100 games in averarge on steam wish list,
from time to time i get me several of these games as 'test'
versions.
Only if they turn out to be reeally good and also have multiplayer i later then buy them on a steam sale.
In very rare cases, like once a year max, i also buy a hyped game as either EA or when it comes out.
Sadly i have often not been very lucky in doing so and wasted so much money by that equally EA and games out of EA, which were hyped and utter bullshit, that i tend to not do that anymore or only if i have extensive "lets play videos" which show me more or less all about the game. One game were i did not regret buying it immediatly was Stellaris of late. Great game, huge mod community and well Paradox shows commitment to improve it.
ÊDIT: gog is great for test versions, but my consumer mentality and weakminded convenience nature brings me back all the time to buy in steam. The integration of chat and voice, the mod workshop and steam forums for each game are all good benefits to me.