Really, gutter guards don't do what homeowners want them to do ... prevent the task of cleaning eavestroughs ("gutters" to Americans) twice a year, spring and fall, or if just once, late fall. Mostly they just prevent the free flow of water, the most important job, as they clog up with debris.
But really all you need to do is clean them yourself, or hire someone. Around here the average house and detached garage will cost you under $100 ($US 70), typically $60~85 ($US 45~64). Not only does it solve the problem, it also means there is someone who knows what's what inspecting the condition every year.
Maintaining eaves and gutters is the key to saving money; in good condition overall all you usually will need is a little of the specialized adhesive caulk and a few screws and brackets replaced. Very inexpensive, and easy to do yourself if you don't mind climbing a ladder. Keeping on top of rotting wood or damaged aluminum will also save you mucho dineros in the long run.
I have often worked in the field with a buddy who bought the tools and a machine to custom-create heavy duty troughs (we would make them up to about 18 m /60' ... anything longer you do in two parts, as you can't keep them from bending when you try to install them). We do an excellent job, much better than average, where a company is all about doing the job as quickly as possible.
Getting a good contractor is the key, and with this particular task, you want a smaller firm that cares a bit, versus a big crew that does large commercial jobs. New construction is very different than homeowner work where you need to take the time to do it right when there might be damage from water already, and small, simple repairs pay to avoid big costs later. Just having a cleaner have a close look at everything is worth the money in the long run.
