Increasing your storage space is always a good idea if you happen to have a lot of valuable items. Although the items and weapons in your Silver Storage are susceptible to rusting regardless of whether or not you've received a blessing from the Royal Court, the Silver Storage is a good place to store your valuables while you're out there questing. It's also a good place to store weapons as long as you've applied some oil to them.
Increasing Storage Space
For now, the only ways to increase the size of your storage box are to either equip a rare weapon with the Merchant and/or Hotel attribute or join a clan that has the Merchant and/or Hotel ability. When you have either of these abilities, you'll have an additional 20 storage spaces.
Storage Size in the Past
Before the DC Upgrade on April 8, 2002, the size of a character's storage box was determined by the character's level. Today, every character has 80 or 100 storage spaces regardless of level.