IMO legislators should spend most of their time (at least until a reasonable "break even" is achieved") striking old, erroneous, irrelevant laws.
For example, many more opportunities to cause government shutdowns, and many more must-pass bills that can be loaded with pork.
ftfy. and I'd add that being from the US, I'd expect that sunset clauses on all laws would have the effect of giving the legislators something to do other than raise money for reelection.
I also think it would encourage less partisan and more consensus-built legislation if the number of votes it passes with extends the amount of time before it sunsets, esp. if the relationship is not linear. Right now, if you have 50%+1 vote in the House, and 60 in the Senate, you don't have to care about the rest, so you can make legislation as extreme as you can while remaining within those boundaries. But if the difference in getting extra votes is a renewal vote in 25 years (with, say, 3/4 supermajority passing) versus just 5 years (50%+1), those extra votes may well be worth fighting for with some concessions.