The more complex a spell the longer it takes to cast, the more lynchpins it requires, and the harder it is to maintain. Also it requires more power to cast. Below I’ve included a table of approximately how long it takes to cast spells of various complexities.

1- 5-15 Minutes
2- 15-60 Minutes
3- 1-3 Hours
4- 3-5 Hours
5- 5-8 Hours
6+ +3 Hours each

Maintaining
In general it takes 1/4 of the casting time to maintain a spell, each day. For Logrus user’s it gets much worse near the pattern, reaching 1/2 of the casting time.