My memory usage hangs around 25% (swap is generally 1%) on my dedicated server and load is around 2-5.
My host recommended that I upgrade from 2GB of ram to 4GB so that I can increase my innodb_buffer from the default 16MB to 2GB. My innodb table size is 2GB.
My question is, given that ram usage is 25% does it make sense to upgrade ram? Queries are hanging sometimes, so I'm thinking that a bigger innodb_buffer could decrease load on the database, just not sure if I really need to upgrade my ram first.
I would recommend making the buffer larger, but still within your existing memory footprint, and see what the performance increase is.
By the way, I can't argue enough for having metrics to look at and graph when you change your settings. Humans have enough cognitive biases that we need to look at hard numbers, rather than go by "oh, it feels faster"