Pears take 6-8 years to begin bearing fruit
(http://www.efn.org/~bsharvy/edible7.html#PearEuropean). Generally, if
you need to add a year each time you transplant a tree.

Pears generally need a pollinator; a late-blooming Asian pear will
work (unless you have a late-blooming European). Also, bees are not
very fond of pears, so it helps to put them close together, and not in
the vicinity of anything more appealing to bees.