Now that you know the Fox, you can spend cash to restore all your SP, which will probably help in a run given how much yen you come into during regular grinding. Just remember to heal up before you ask the fox for a restore, since it'll give you back ALL your SP.The price per SP restored goes down with each level of the link, but you need to complete certain quests to level up. First you have to go to the shrine and select "accept the ema's request" to initiate the quest. ACCEPTING THE QUEST DOES NOT USE UP TIME. When it's finished, you report back the fox, which uses time. The fox is available whenever, but rainy days are the best time to report in, since there's not a lot to do on those days.