When they are younger, I found that I could be in an adjacent room where I could still see the play yard and my daughter would still play independently. This was important to me to not only let her gain the independence, but also get more comfortable with the idea myself. As she lengthened the time where she could play in the play yard, I could continue to add to chores that I could get done during the time that she was playing independently - and eventually it could even turn into a long enough period of time that you could get something essential done like take a shower.
For us, starting independent play time (IPT) early on really helped, because it eased the transition into the next phase of IPT once your child becomes a toddler... room time. Room time is a challenge all its own, as your child grows, they begin to explore their surroundings and want to expand their boundaries. Making sure their room is child proofed and a safe surrounding to have your toddler in for short periods of time independently is the foundation, once that is completed... you can begin your transition from IPT in the play yard, to independent play time in your child's room - or as we call it around our house, "room time".
Room time for us started early, before Cupcake's 2nd birthday actually... she was well adept at keeping herself entertained for up to a 45 minute period for IPT and was ready to drop her first nap. (When I had been taking my shower.) At this point, we decided to transition to toddler room time during her original first nap time and it has worked out great as far as time of day for us.
We started the transition over Christmas break while my husband was here to help with it. Once you begin the transition, it is like "starting all over again" - starting out with a short amount of time and slowly adding to it. We started out sitting in the room with her for the first week, then trialed room time for a short 5-10 minute period in the beginning - with one of us sitting outside of the door. That went well, so we slowly started adding to it and could move to other areas in the house on the second level. (Her baby monitor would be left on in the room of course, to hear the activity that was going on... and you could also use a video monitor during this time if you had one as well.)
Eventually, room time turned into the time on our schedule when Mommy was able to go take a shower, and also conveniently lines up with Peanut's morning nap time. (See my post on daily schedules for more about lining up a baby and toddler schedule together.
I'm very glad to have found out about the concept of independent play time and room time through our Babywise groups... these have worked out great for us and are an important part of our schedule each day. Do you do IPT or room time at your house?
Here's the link to the SAHM September video on Independent Play Time: