I've had a year round tree for almost 20 years now. It started with a small 2' tabletop tree, but not I use a 6' skinny tree in the corner of my living room.
Heres' show I do it:
January-snowflakes, icicles, snowmen
February-hearts ( I have blown glass hearts and red and white glass hearts, along with red glass balls that have white crocheted snowflakes, and purely Valentine's ornaments-polyresin ornaments that look like Valentine cookies and candy, along with red and white checked bows
March-usually spring stuff, this year Easter-crosses, carrots, bunnies and eggs
April-spring flowers
May-around the middle to the end of May, I switch over to patriotic things-red, white and blue lights, ornaments, flags, Uncle Sams, etc. It stays like this until August, then
August-back to school tree-crayons hotglued together and wired to the tree, pencils, little notebooks, scissiors, etc along with a back to school ribbon and fabric strips that I tie on the tree
September-fall
October-Halloween
November-Thanksgiving
Christmas-jingle bells
I love decorating this tree for each season or holiday, and everyone seems to enjoy seeing what i come up with for each one, especially on the monthly breakfast days!