im also quite new here, but oh you have been busy .. 530 wishlisted titles is something :D

Another thing worth mentioning is prices have been rising, and by a lot in some cases. It could be because of inflation that affects everything in general, but I have noticed a pattern of increases clustered around specific publishers of popular franchises, like Star Wars, Disney, etc. You may need to wait years for those prices to start dropping, and even then, inflation might continue to stubbornly keep prices high.

Yes, ITAD seems to have an issue with KoTOR 2. There seems to be 2 entries on ITAD for KoTOR 2, but the second one has a fairly low current deal: isthereanydeal.com/search/?q=knights+of+the+old+republic#/page:game/info?plain=starwarsknightsofoldrepubliciis ithlords (US$2.50 on Nuuvem), but it's not the lowest price ever though.

I'm not sure why it doesn't capture the price history on GOG however, but you can see the recent GOG price history on GOGDB: https://www.gogdb.org/product/1421404581 the lowest which was $2.49 on Jun 6 2017. Hope this helps if you're eyeing KoTOR 2.

Edit: had to edit the ITAD URL because GOG messed up the link structure :(

I've already assigned some funds for Summer Sale :D

Bonus games given by GOG usually drives me to buy more, because free games are often really interesting (Starcrawlers, Hard West recently). Also bundles often make me to buy more games, even if most of them are not even on my wishlist (like HoM&M series recently).

And some of discounts during last Summer Sale were so deep that I've bought 2-3 keys for friends (as Avernum, Redemption or Arcanum around $1 or even below).

I miss this kind of sales.

My Christmas budget is still waiting ;)

I'm using Isthereanydeal.com, but I'm very gog-centric in that. Usually I look at all time GOG low, not at all time low in general. I believe DRM Free is worth paying a little bit more.

When does the next weekly sale usually start? I should know this, but I've been distracted from the clockwork and I lost track of it. This weekend sale looks good, and I could blow too much money on that if I'm not planning ahead for the summer sale. I think maybe my best strategy will be to wait until the next weekly sale comes out and overlaps with the current sale, so I can make comparisons and decide what to not buy and save for later.

This is exactly what I do. I think of the GOG price as the "real" price, while all the other prices are weird rental prices that make no sense to me for why anyone would want to pay for them.

Next sale will me Summer one, right?

Most probably. I think summer sales are pretty huge too. Regardless of which site.

Yes. In previous years we had Summer Sale in June and usually nothing in May. In Poland first days of May are holidays, second half of May is probably time to get prepared for the big Summer Sale. We had also big sales in March and April, so I would not expect anything big before June.

2017: Summer Sale - - - - 6-20 Jun
2016: Summer Sale - - - - - 8-17 Jun
2015: DRM-Free Summer Sale - - - - - 3-19 Jun
2014: Summer Flash Sale - - - - - 13-29 Jun
2013: Summer Sale - - - - - 18 Jun - 4 Jul

I really liked the 2016 summer sale where you got free games if you crossed a specific spending threshold. I got spelunky and dreamfall chapters along with another game when i hit the 15 dollar mark. I kind of wish they would bring it back again like that this year.

Are there data on the different gimmicks of each year's big sales?
Like the loot boxes or xp for purchasing games.

I ask because Kotor is on sale, but it will no doubt be on sale for the summer again.
And if summer sales had gimmicks I'd like to get in on them.

Steam Summer Sale starts on June 21st.

That means that we should expect GOG Summer Sale starting:
- on June 5th - in case of two-week sale
- on June 12th - in case of one-week sale

Is that even confirmed?

I think they've based it off of most if not all past big sales. Usually a week or two before Steam's.

Is Steam sale date confirmed, then?