Cut for the Bush or the Bloom?

If you cut with the bush in mind, stem length must sometimes be sacrificed.  Ideally, the bush must keep a certain shape, growing outward so that the stems don't bang into each other and don't compete for light.  If no convenient five-leaflet set is facing away from the bush, or if the stem is on the short side of average and what you really want would require taking everything, then you must cut shorter stems.  If a bush is very young or acting poorly, then it is wise to cut shorter stems because these bushes need all the help they can get, including the food extra leaves may generate.  You'll feel better about your short-stemmed roses if you dwell on the good what you leave behind does for the rest of the bush.

If you must, you can cut for the bloom anyway if you want to enter a rose in a show and know you'll need all available stem length to have a prayer for a blue ribbon.  Or you may have just purchased a new crystal bud vase that will show off the stem and foliage of your prize blooms.  In those case, I say go for it.  Just acknowledge that you're being piggy and resolve not to do it more often than necessary, or bushes will wither from your greed.

Some people may have told you not to cut blooms from first-year bushes:  pay no attention to such silly advice.  Even though you dutifully leave a bloom on a bush because you've been told that new bushes need all the foliage possible to generate food, you must cut it off anyway when it begins to drop its petals.  Otherwise, the bush thinks it's time to "go to seed" and will expend energy developing the hip, a rose's seedpod.  What can possibly be gained by leaving the bloom on the bush for these extra few days, a week at most?  If you planted roses for garden display, that's one thing: leave them and gain the few extra days' work from their foliage.  But if you want blooms in the house, take them.  Just be kind when you know you must.

Keep in mind that a new rose can have a stem only as thick as that from which it was cut.  If you cut from twigs, you'll get more twigs.  If you're going to be disappointed with the stem you're about to cut and see that only spindly growth will come from where the cut is made, cut back farther.