There are hundreds of options, and even on my cruising boat I have tapered halyards and sheets
, and all sorts of fancy rope
work. I like doing it, and it hurts my feelings to have bigger lines than necessary, plus by doing it myself I can get high performance line at lower cost than less expensive lines.
That being said, unless you like rope
work, and know how to do it, paying someone else is much more expensive.
For a small daysailor I would probably just go with all Sta-set line and replace everything with whatever size you already have there. It's reasonably priced, and will work for pretty much everything on the boat so long as minimum hassle is what you are after. It is also pretty ubiquitous in sail shops.
if you want a more detailed look at lines let me know and I will give you some recommendations for a more complicated (thou not more expensive) set up, but it will be more work.