In Spain it is common to leave 5% -10% tip for services.
Locals always tip even if modestly, it is considered polite and the Spanish are sticklers for manners and etiquette.
When tipping you should always include the waiter in a restaurant a bartender in a bar, a taxi driver, a toilet attendant, and hotel cleaning staff.
There are no added service charges on the final bill at any hotel restaurant or bar, unlike France.
if you are uncomfortable with tipping then just do what the locals do and leave the change discreetly under a plate or something. Don’t forget these service staff work hard for little money and any extra is always appreciated.
Intresting fact about tipping!