I moved from 21' to 32' eight years ago, and found many differences.
Much of the advice above is good, and my suggestion is to pay close attention to two factors that will bear significantly on costs, maintenance, ease of sailing and overall enjoyment:
1. What is the change in displacement (not just the increase in length);
and 2. How complex are the systems on the new boat compared to the old?
My last boat was a Freedom 21, which displaced about 2,000 pounds and had hardly any mechanical, electrical or plumbing systems of note. My more recent boat is a Morris 32, which displaces about 12,000 lbs., and has much more complicated and expensive systems, including hot and cold pressure water; engine driven refrigeration; fresh and waste water systems; 6 winches plus windlass (versus 2 and none on the Freedom); a real electrical system with 3 batteries, small inverter, dockside and engine driven re-charging capabilities, etc.; a galley with propane stove and broiler; etc., etc.
Comparing the costs of operating a new daysailor/weekender like the Freedom to a used but larger and more complicated diesel engined boat is certainly like comparing apples and oranges. Some of the costs are difficult to compare because I moved from a large inland lake (Lanier, near Atlanta) to salt water (Cape Canaveral). Nonetheless, without adjusting for inflation over the last 20 years here are some differences:
Dockage: I now pay per month what I used to pay per year at Lake Lanier. That's not due to the size difference particularly, just the tight market for dockage in Florida.
Insurance: Up more than 12 times, due to a ten times increase in price and greater risk in Florida.
Sails, standing and running rigging: Much more expensive due to the larger sizes in all dimensions (length, cross-section, and weight). E.g., sails not only contain more square feet, they are built of heavier cloth and they include features on bigger boats that aren't often found on smaller, lighter boats.
Maintenance and upgrades: Vastly higher, but also quite variable depending on how much you will do yourself and what kind of condition you want to keep your boat in. Many folks say to plan on 10% of the initial purchase price of the boat as a recurring annual maintenance and upgrade figure. That's only a crude rule of thumb, which I've occasionally exceeded and sometimes come in below. I will caution you that it's hard to overestimate what it costs to replace or upgrade pieces on a more complicated boat, particularly as it increases in size.
Other operating costs: probably will increase not just because of the increase in size, but also because you may well travel further in the larger boat.
There's a lot to be gained when going from a boat in the mid 20's to one in the mid 30s, including speed, carrying capacity, more comfortable motion, more luxurious accomodations, etc. But you're also getting to a boat size where you can't manhandle hardly anything. Plan ahead, use the mechanical devices onboard to ease the work, and you'll be OK.