وسبب وجوب الوضوء الصلاة عند البعض
Some jurists regard the obligation of prayer as the cause of wudu.
وقال البعض: سبب وجوبه الحدث، ووجوب الصلاة شرط
Others treat ritual impurity as the cause and the obligatory prayer as a condition.
These accounts analyze different legal relationships. One emphasizes the need for ablution when an obligatory prayer requires purity. Another identifies the state of ritual impurity while retaining a connection to the requirement to perform prayer.
A person's loss of wudu does not necessarily mean that every passing moment creates a separate obligation to perform ablution immediately. The terms must be understood through the relevant act of worship.