Quite right. Scutage was supposed to be a sometimes food, and abusing scutage by both raising the rates and imposing it in peace-time was a direct cause of the First Baron’s War and the creation of the Magna Carta.

And while we’re on the topic, let me answer this ask from @kuvirametalbender:

warsofasoiaf:

Tagging @racefortheironthrone on this in case I missed something, to add something, or just to dunk all over this question because this is something he understands very well.

Scutage itself evolved in the High Middle Ages where kings would levy the tax in lieu of feudal service, so during peace time, the military wasn’t much different from the levy model, in peace time the scutage wouldn’t be collected any more than the levies would be called. King Richard I would exercise a royal prerogative, deciding whether a tenant would be liable for levies or for the scutage. However, increasingly, the scutage became levied in peacetime, King John the Softsword often levied a two-mark scutage every year, this was one of the big bones of contention with him that led to the First Baron’s War when he levied an unprecedented three-mark scutage in 1214. The Magna Carta forbade scutage save by “the common counsel,” which was the Great Council, a council of barons, bishops, earls, essentially the tenants-in-chief which gradually evolved into the Parliament of England. In 1217, Henry III would often levy the scutage but usually after formal buy-in from the barons. This method of taxation lasted until the early 13th century, when royal taxation became more standardized and better enforced under King Edward II.

Typically in the time period, kings and nobles would have a small retainer who would be in their direct employ, men that they paid to help keep the peace, enforce edicts. This was an obligation, hence why the knight’s fee was the actual level of income needed to provide equipment for the retinue to fulfill the feudal obligation of military service. Depending on the king in question, they would often mandate a certain level of military readiness among the population, such as equipment and drill days, which were enforced to varying degrees of success and set by property holdings and wealth. Key to this was the yeoman class, who ranked below knights, squires, and other landed gentry but above pages. Yeoman, a distinct medieval middle class, were professional or semi-professional warriors often serving as bailiffs and constables, as well as the franklins, who were freemen and often served as aldermen or mayors, and usually required by different royal edicts to maintain a certain degree of equipment. As such, there was a very distinct hierarchy of class that factored into military readiness. The first full-time professional army in the medieval era in western Europe is typically identified as being in France, the army of King Charles VII of France, in 1445.

Thanks for the question, Anon.

SomethingLikeALawyer, Hand of the King

Once scutage was more commonly practiced, what did Nobles did with their time, not having to go to wars? Also in the case of an invasion, of a noble’s land was the King expected to use the tax money collected from other nobles to defend the area under attack? Are nobels not expected to raise their own banners anymore since they’re paying a military tax?

Well, some nobles still went to war – after all, war was still for the elite a way to gain royal favor, land, money, and fame, whereas scutage was primarily useful for small landholders who couldn’t afford the costs of campaigns (and who would be unlikely to gain royal attention and favor in battle, given their lowly standing) – but it was now more at their discretion.

But in the most part, the nobility occupied their time by managing their estates, entertaining themselves, socializing and gossiping, or engaging in local, regional, and national politics, just as they had always done.

Finally, yes, the king was supposed to defend any part of their kingdoms from invasion – it’s not really the case that they would refrain from doing so because someone hadn’t paid their taxes because it was still a huge loss of prestige and invasions are rarely that discrete.