When is a good time to wean my baby off of nursing or bottle-feeding?

Depends on the child. Some kids need more nurturing than others and will seek out the cuddle time at the breast well into the 2nd yr. If your infant needs cuddle time, do as long as desired. When kids start to walk, they may loose interest in cuddle time. When you have to chase them down to bf its time to quit. Bottles are easy, when baby will take well from a hard spout sippy cup start the wean.
Six to twelve months. The maximum benefits for breast feeding are the first six months of life. It is certainly beneficial to breast feed through the first year. I recommend weaning off the breast or bottle starting at one year of age terminating bottle or breast by two transitioning to a cup.