I was checking the rules for recharging a staff, and it mentions that you need a prepared slot or daily spell slot to cast and recharge a staff, but could a spell-like ability be used to recharge a staff?
Recharging Staves: Staves hold a maximum of 10 charges. Each spell cast from a staff consumes one or more charges. When a staff runs out of charges, it cannot be used until it is recharged. Each morning, when a spellcaster prepares spells or regains spell slots, he can also imbue one staff with a portion of his power so long as one or more of the spells cast by the staff is on his spell list and he is capable of casting at least one of the spells. Imbuing a staff with this power restores one charge to the staff, but the caster must forgo one prepared spell or spell slot of a level equal to the highest-level spell cast by the staff. For example, a 9th-level wizard with a staff of fire could imbue the staff with one charge per day by using up one of his 4th-level spells. A staff cannot gain more than one charge per day and a caster cannot imbue more than one staff per day.
I was reading this thread, and they kept using summoner's summon monster (a spell-like ability) as example to recharge staves.
Yeah, I'd agree, by the rules you probably couldn't get away with that. On the other hand, it's probably close enough so that most GMs wouldn't mind if you use an SLA to recharge a staff, especially if it's limited in uses per day.