Weapons and armor break?  It's not that I mind, but I find it fascinating that this is the first I'm hearing about it.  I swear every single Breath of the Wild thread has people complaining about the weapons breaking.  I think people just love to hate on Nintendo.

Anyway, I plan to get to this game eventually.  This is my way of tagging for later.

Yes, all weapons and armor degrade and break over time (breaking just means that you lose all stat benefits from them as I recall, you don't lose them permanently if they break, they can still be repaired). You can find blacksmiths in many of the small towns and cities in the game that can repair your weapons and armor for a nominal fee, and they also sell repair kits which you can carry around in your inventory and use to repair your equipment in the middle of quests and such.

Combat wise, I personally recommend investing quite heavily into Quen and Igni. Quen is invaluable in witcher games, it is a spell that protects you from damage, and at the higher levels you can actually use it to absorb enemy damage and convert it into health to heal Geralt. Igni does great damage when fully specced, when I played I basically turned Geralt into a human flamethrower. Or if you find melting enemies with Igni boring, which some do, you can just invest in quen and then go down the combat tree from there, focusing on either light or heavy sword attacks. 

I played for about 4-5 hours before my first sword broke. I'm sure I went through 20-30 weapons by that time in BOTW. So, it's really not the same.

I played good guy Geralt and was swimming in cash by late game, as long as you do alot of the question marks on the map as you go and sell all the unneeded loot that you collect at those places to merchants regularly, money shouldn't be an issue. There are actually very few things that you need to spend money on in Witcher 3, food items for healing occasionally, blacksmith blueprints every now and then, any Gwent card you come across. The blueprints for the best armor sets in the game, the Witcher sets, are found piece by piece at various question mark locations, once you get a full set of those blueprints for the set that you want (there are 4 sets in the base game, and 1 more in each DLC expansion), you don't need to buy blacksmith blueprints anymore since they are all weaker than the Witcher sets.

I believe Witcher 3 has no hard level cap, but if you over-level quests by too much, the experience you get for doing them drastically decreases, so you want to always prioritize quests that are slightly below your level or right at your level, instead of trying to do ones that are above your level, because if you do the ones above your level first and then go back and do the lower level ones later, the XP rewards will be much lower. If you do all main game and DLC quests at the proper levels to maximize XP rewards, you will likely hit about level 60. There is however a cap on the number of ability points you can earn, I believe that cap is 70 in the base game, raised to 100 in new game+. You get 1 ability point per level, plus there are certain areas on the map which award bonus ability points, so you can hit the ability point cap without doing every quest in the game and DLC.