Being single, I almost envy CathMomof7 for the regularity that her situation promotes. My practices are far more erratic. Some days I'll say all three Mysteries, then go for days without saying any. I just got this, which may be good:
http://memoryrosary.com/
The Memory Rosary is not intended for helping people to delay finishing 5 decade Rosaries for more than one day. You still need to keep your decades together, and should finish 5 decades within a one-day window. If you want to go for a second Rosary, you ought to strive to finish it the same day. Same for 3 Rosaries: get it done within one day, if at all possible.
There are a few principles to keep in mind for Rosary indulgences.
If you'd like to get an indulgence, you should remember that one decade has no indulgence. Nor is there an indulgence for 2, 3, or 4 decades. You have to pray a 5-decade Rosary (one-third of a complete Rosary) to get the first indulgence. If you are experiencing any interruptions, you should try to get back and finish the decade you were on, at the very least, within a short time, depending on your situation. I think that means as soon as practically possible, or, at the first opportunity. But in any event, you should finish the 5 decades in one day, if at all possible.
When I have neglected to finish one decade for an hour or more, I like to start the decade over, just to be sure.
Overall, indulgences apply to one who is in the state of grace. This is reflected in the words, "under the usual conditions," found in the indulgence description after some prayers. If you need to get to confession to be in the state of grace, you can still benefit from praying a Rosary, but you will not receive the indulgence until you make a good confession.