I am confused with a number of issues.

1. I have three Thunderbolts equipped. If I use two and want to craft more it says
I already have this item even though I have the necessary ingredients.
If I'm not mistaken it says this even when I have none left.
( has alcohol got something to do with replacing these potions?)

2. The red hammer with a minus number on a weapon sometimes exists even when the weapon
condition is 100%.

3. Is it better to use a weapon matching your level even if the damage it provides is less than
say a weapon a few levels lower? eg. I have a crafted viper sword with damage it inflicts somewhere
between 90 -120 but it is a level 1 weapon and I am on level 5.

Anyone care to help?

1.When you rest items are refilled if you have alcohol in inventory.

2.Never experienced this, are you sure another weapon is not damaged?

3.Only damage matters as far as I am aware.

Hi Boeriemore

1. meditate and youll restock your pots it does take alcohol to replenish)

2. Ive not ran into this myself but I have had the overburden bug and if you unequip and re equip it clears it. Might try this with your weapon might work

3. It would be impossible to keep making new gear for each level gained. Im lvl 35 and still using the mastercrafted feline stuff and it is still effective but if there was better gear for that level I would be using it.

1. All oils, bombs, tinctures etc. are permanent. They are refreshed by meditating.
2. Never seen that.
3. Level is just a guide. Go for the higher damage.

Once you craft a potion once you never need to 'recraft' it. As the other poster said, as long as you have some alcohol in your inventory and you rest (even just for 1 hour) all known potions will be instantly refilled and you will be good to go :-)

1. You can just drop used bombs etc. and make them again. Useful when you don't have alcohol.
3. Right lower corner shows you DPS and this should be guide for you.

Thank you all for the help Will give it a try. So alcohol automatically refreshes all potions - does this include beer?
If I wish to increase the quantity of a particular potion do I have to drop what I have before being able to make more?

I had to give up "Wandering in the dark" as I had no food, nothing left to
continue this long quest. (the rats drained my health)

No. It is not 'alcohol' that refreshes oils, it is spirit particularly. Beer is for getting drunk. :) No. To upgrade any potion or other item, you need the original lower level item in your inventory, as one of the ingredients.

You need nothing for refill your potion or bombs.

You need Alcohest, Dwarven Spirits (I had so many of this in my game I filled 2 stacks with 100), etc as you will automatically use one to replenish your stock of potions and bombs.

Don't look just at the damage. You may find a weapon that has a slightly lower DMG, but additional buffs fit more to your play style. For example, if you are using signs alot in fights, it's better to equip a bit weaker sword, but with bonuses to all signs or those you use the most.... well, unless you are playing "Rambo Style" - in that case, DMG is everything.

Also, you can find some weaker sword, but with slots for runestones. This may benefit you more if for example you'll add a chance to stun or bleed. Of course, that makes no sense if DMG is significantly lower (let's say 30+ points for lvl 30 sword).

In other cases, take the weapon with higher DMG. It doesn't matter if minimum level required for it is much lower than your current level or not.

These answers are all based on my experience before patch 1.07.
1. You need strong alcohol. I had temerian rye work to refill potions. You must mediate for this to work. If you do not feel it is safe where you are to meditate then you can drop the potion which will give you the chance to remake it using alchemy.

2. The little red hammer is the difference between the base damage value of the weapon in your inventory and the weapon you have equipped (steel vs steel; silver vs silver).

3. The level of a weapon (and armor) is determined by the game (it is not hard coded) based on some esoteric formula that takes the base damage plus other properties of the sword into account. However, as LameWarrior pointed out, you need to look at those properties to see if they are even important based on your play style. For example, once you start to use superior thunderbolt potions you have a 100% change of getting a critical hit so that property on a sword has very little value.
Also, I do not believe the formula for sword (or armor) level takes into account rune slots.

thunderbolt -30s
enhanced thunderbolt - 60s
super thunderbolt - 90s

Look into upper left corner of your screen may be.

In general, in-game information is based on the patch in effect. Information you find on the web is not necessarily based on the current game. Look at some of the dates and you will see some of the information was posted before the official game release.

Note: You can only refill potions by meditating. Fast travel, even for several days does not refill potions (though I think it should when travel time is at least 1 day )