The spike and ferrule system of hanging aluminum and some copper gutters is an installation system that generally mounts the gutters tight with the fascia. This in turn will allow the wood to stay dry. Bracket hangers should be installed on blocks to create this airspace. Some contractors will replace the fascia boards with pressure treated wood to try to overcome this problem. Usually this will only create a fascia that paint has a hard time sticking to.
Continuous gutters are by far the best long-term installation.
If the gutters are copper, they can be soldered into one continuous piece. This is about the only good application for a pop rivet. Also, check that the downspouts don't get narrower as they get lower. Sheet metal screws are tighter but still are not as tight or as long lasting as bolts. Bolts should be stainless steel or brass with self-locking nuts.