I have a jade plant that is about 20 yr.old I got it as a gift last year. I noticed branches would get soft and break off.I only water it about once every 2mo. I'm worried about watering it more because I know thay will turn to mush and die. Any sugestions? Barbara

Two months between waterings seems too long and that's probably why your losing branches. I water mine once every two weeks or so in winter, usually once a week in summer, "IF THE SOIL IS DRY" As long as the pot is not too big and the soil has good drainage, it should dry out within a week or two if kept in reg indoor temps.
The pot should not be any bigger than an inch around the root--ball. Check weekly or so with your fingers, feel way down in the soil as far as you can, or through the drainage hole for dryness. Empty out any excess in the saucer after watering so it's not sitting in water.Make sure you water enough so water comes out the bottom getting the whole root-ball wet, not just the top half of the soil.
Make sure it's getting bright light and direct sun or the branches can become weak and need staking. If you give it more sun if it's put outdoors,do it gradually so the leaves won't burn.