I am new in MW. Loved the big world and started to explore freely around, leveled up fast and cleared many dungeons here i found strange artifacts. Now, after looking from (about artifacts) net it appeared, that they are actually quest items and quest caves.

Now i am worried i broke some quest Is free exploring safe or i may broke quest by destroying artifact or killing crucial monster?

Finding artifacts and killing monsters is safe. Killing a few crucial NPCs is not but you'll get a dire warning if you do so you can reload and continue.

Morrowind was designed to allow you to explore freely, that's one of it's greatest strengths. And it's typically pretty good about handling quest-points which were stumbled upon by accident and out of order - like killing a quest NPC or taking an item. I would recommend avoiding killing NPCs who are not hostile in dungeons as they may be a captive which you have to rescue or something of the like. However, even if you kill them, you should be able to continue that quest line, you just might miss out on a reward.

If you kill an important quest-related NPC you will see a message on your screen telling you ""the thread of prophecy has been broken." If you see this message you have a choice: you can either continue and take your chances or you can reload. Having a choice like this is one of the great things about Morrowind, in my opinion.

As Melchior Dahrk says, Morrowind was designed with exploration in mind. My experience is that, unlike Skyrim, it is very hard to break quests or quest lines by exploring.

If you sell a necessary quest item or leave it on a corpse that vanishes that would be a quest breaker. When I explore that is what I do. I only find places and recon what is in them. Lots of locations spawn occupants and you can slaughter away and loot to your heart's content. Just take all loot on any corpse and then dispose of the body. Exit the location and re-enter. New occupants will have spawned. Good luck!

'If you sell a necessary quest item or leave it on a corpse that vanishes that would be a quest breaker.'

Tought so. Thank you for answer, so it is not safe after all. I killed lots of enemy guys in dungeons and left them rot, because they usally had nothing valuable with them., and i dont want burden myself with socks, rusty armors and odd stuff. Also sold some strange but very valuable items.

Leaving a quest item on a corpse is a potential game-breaker, so it's safer to loot the corpse and dump the items on the floor, in case you ever have to go back. The corpse will disappear after 3 days, but the items will remain. Selling a quest-related item may or may not be a problem, because in some cases you can buy it back, but not in all. If the merchant equips it (fixed by the Morrowind Code Patch), you might have to resort to killing the merchant to recover the item, or if it's not equipped and their inventory resets at some point (which varies from case to case), then it's gone.

A few of the quest-related items are "named", as in "So-and-so's Trinket", so it's at least somewhat obvious that the item is either stolen or unique. In a lot of cases, "named" enchanted articles spawn as random loot, so it's not always apparent that something is truly unique, but you might want to hold off on selling them unless you spot a second item of the same name in loot or for sale. Most (but not all) unnamed quest items can be replaced or substituted with generic items, so if a TG quest calls for stealing a generic item from a target, you could just buy one to satisfy the requirement. In a few cases, the specific item from a specific place MUST be used, but it won't "stack" with the generic item, either in inventory or storage. I suspect that in 99.9% of the case, socks, rusty armor, and such will NOT be quest items, so you may still be good so far.

Thanks, but i better give up free roaming now and start questing. I can explore rest of the world near the end of the game, or after final quest, if it is possible to continue.

Yes, you can continue exploring as you desire

The MQ is not the end of the game at all. You can continue playing 50 hours or more after if you want to.

You don't have to give up exploring. There's some good advice in this thread, which, if taken, should leave you with minimal worries of operating in Morrowind outside of a quest - or even of being tangential when performing a quest.

Any damage which you think you may have done is done.

Exploration and looting are integral parts of the game. Doing a few quests might be a good idea, but there are a LOT of quests, and you're never going to be able to complete all of them with a single character anyway. This is not a game for "completionists". It's pretty hard to break the MQ accidentally, and most of the other major ones are pretty resilient. In quite a few cases there are "spare quests", so you can do another quest instead to get around it (there's even a "back path" to the MQ, if you "accidentally" kill a couple of the major characters). If you break a couple of minor quests, so what? Meanwhile, you can do BOTH: tackle a quest or two and explore a few places along the way.

Essentially, I just play the game according to whatever the character would do under the circumstances, and whatever happens, happens.

There is time limit?

Basically, if something has a unique name, some NPC somewhere may want it for a quest, so keep it somewhere. There is enough generic loot to sell that keeping things you find won't put you in the poor house.

If your on the PC, the House Under the Hill, or A Good Place to Stay (different versions of the same house mod) have excellent areas to display your swag.

No. Get to it when you get to it.

No, no limits except your own patience. You can play as long as you like although eventually you depopulate all the caves and mines. Creatures respawn but people don't.

edit: If you're on PC you can add mods and keep going forever.

No time limit. You can play with one character for as long as you want. There is so much to do in the game.

The only time-limited quests in this game are if you have to accompany some NPC from a location A to a location B. But even during these quests, NPCs will remind you how much time you still have left if you take too long. Apart from that, I don't recall any time-limited quests though maybe there are some. But there definitely aren't any time-limited quests during the MQ.