Depends on the game you're running - by 'DM' I'm guessing the current edition of D&D ("5e").
Magic items, in general, are de-emphasized in assumed 5e play. That is, the game doesn't /need/ magic items to run more or less smoothly (something that only bears saying relative to other editions that did assume aproximate numbers/types/power of items would be acquired by a certain level). Rather, magic items are a tool for the DM. Consumable magic items like potions can make up for a lack in the party's abilities, place some healing potions if you plan to have a particularly brutal 'day' coming up where you feel the party's healing abilities may not get them through it, for instance. Permanent items are much more highly prized and powerful, both to the players - a serious magic item, even a simple +1 weapon, makes the character litterally just /better/ than he is without it - and as a tool for the DM. You can tailor magic item placement to give an under-performing PC a boost, to add capability to the party you want it to have going forward for campaign reasons (for instance, there are some monsters they'll need magic weapons to hurt, if you want to use a lot of such monsters for the balance of the campaign, placing items that work on them open that up, it not just gives the players the capability, it gives a reason why others might call them in, or come into conflict with them, if the items are that rare), to encourage participation in an adventure, and/or to paint a sense of the campaign world. Since items represent power above and beyond what the game is designed around, you don't want to give away too many of them, either, so it's a good idea to get a lot out of each item.
Cursed items are even more de-emphasized in 5e, again, maybe not compared to the latest eds before it, but relative to tradition. Cursed items tend to be 'gotchyas' that just punish a player for picking up an object or wanting to make his character better, which can produce some hard feeling around the table. A cursed item, usually a custom one, can drive a sub-plot for a while, or even add a little depth to a character, as well give it a hit to its effectiveness. A party's actions could be driven for a while by trying to get rid of a curse (item or otherwise).
Cursed items, and magic items in general, are the kind of thing you can introduce later in a campaign, or in a later campaign, when you start having that sense that "well, this character really needs something, this other one needs to be taken down a peg, this 'quest' could use a better reward, this area of the campaign is a little bland, etc..."