In my book, a senior advisor is really the top of the heap in the advisory profession: they are qualified to make all the decisions regarding their own clients, and typically manage their own client base, supported by (and mentoring) junior and associate advisors. The only “next step” is not a professional advancement, but a business decision to become a partner in the firm. From an employment standpoint, the compensation shouldn’t change from senior advisor to partner, only the additional sharing in the profits or losses of the firm.