Details should not randomly change in your poem, and they should be correct for the place and time and culture. If you are describing an ewer on the dresser, it shouldn’t move to the kitchen table unless you get it there in your poem. Details become much more important in longer poems. If you’re writing an epic poem with 100 characters, you have to keep track of the names and get them right everywhere in the poem. If your flowers are yellow roses in the first stanza, they had better be yellow roses in the 100^th stanza, unless your audience knows when and where the change occurred. So, know your background, and keep those details straight.