How can a Muslim avoid their acts of worship from becoming mere daily routines while maintaining a sincere intention for Allah in every action, and is it necessary to renew the intention before every act of worship?

The doer of acts of worship is not rewarded for them unless he accounts for them [i.e., intends them for Allah's sake], and the presence of intention and seeking reward is essential, based on the Prophet's (peace be upon him) saying: "There is no reward except by accounting [for it], and no deed except by intention." Intention distinguishes acts of worship from habits and distinguishes some acts of worship from others. This is what jurists endeavor to explain. As for the masters of spiritual conduct, they mean by it the distinction of what is intended and who is worshipped, which is sincerity: that by worship, the Face of Allah alone is intended. It is sufficient for accounting that the motive for the act is seeking Allah's reward and that the purpose behind it is to obey His command. What is obligatory is to maintain the ruling of the intention, not to merely state it, meaning that one should not negate one's intention with something contradictory. So, if the accountable person intends at the beginning of the act of worship, it is an actual intention. If they forget it, Islamic law rules that they are still intending and seeking closeness [to Allah], and this is a presumptive intention. A Muslim strives to attain perfection by continuously remembering and bringing to mind the intention, so that their deeds do not resemble mere habits with repetition. Among what helps with this is continuous remembrance of Allah, shortening one's hopes, and remembering the Hereafter.