They need a daily amount of fruits, vegetables, pasta, beans, etc. Don t forget they also need pellets and seeds. It should be at least 24 inches wide. That will allow for more activity. You should get the largest cage that you can afford and have room for.
Safety is one of the most important things to consider when buying a cage.
If the bars are too close together, they can get their toes or beaks caught between them which in turn will cause injuries. The same goes for bars that are too far apart. The more toys you have in the cage the better. The toys will keep them busy and it also helps keep their beaks in tip top shape. Lovebirds' beaks are made of keratin.