Runes of Magic US / AU

Yes, you are wrong, but there are only 3 worth making . lute, tambourine, and guitar. Which 2 that are best for you depends on your class.

Rattle is also good to make, it all depends of your level, class. If you are not going to burn an instance and need more defense, use a rattle.

The instruments you make are for 3 days, i remember getting 7 day ones but i think those are from the musical boxes from the minigames.

Hope this helps ;-)

Lute, tamb and guitar are only 3 worth making. These can be made through Alchemy, Carpentry and tailoring. As zid said you can obtain musical boxes from the chests in malatina which can give you a random 3/7 days musical instrument. These can also be bought/sold on the auction house for in game gold. Rattle has its uses but mostly I would always use the first 3.

It should also be noted that the instruments you craft and the instruments that you obtain from the Musical Instrument Boxes from Malatina's mini-game are SEALED instruments.

That means that you can make / collect / stock up on as many as you so desire, and the timer on them will not start until you right-click on one to activate it.

The crafted instruments last for only three days, but so do the ones from the music box. You have to unseal them to use them. There is a 7 day version that was offered via the item shop. As for just storing the sealed ones from the magic box, that is really no different than just storing the mats to craft them.

The price of the mats for the crafted ones are about 1/3 the price of the the musical instrument box. And then considering that the music box is random, I recommend getting the crafted ones. Get your skill up to level 33 and buy or gather the mats.

As for the instruments:
rattle-good as it increases both defenses. But it takes one of the 40 buff limits, that and I am just too lazy to go make it.
lute-physical attack speed increase. does not stack with guitar
guitar-spellcasting speed increase. does not stack with lute
tambo-both damage increase
sax-reduces enemy damage. utter worthless. Requires to be with a range of 150 of enemy and 5 sec cast time.

All are party buffs, range of 150, 5 sec cast time, share a 2 min cd, and do stack with most stuff. Iirc there are three different speed buffs that the lute and guitar do not stack with, but sry idr exactly which ones. I want to say they are the lute and guitar, the s/p spiritual leader, and some speed pot.

Rattle an Tambo no stacketh either.

It depends on what you're going to use them for. In endgame instances, instruments is a must, because of how much they buff the party's DPS. But other than that, you don't really need them.