budget holders and ICT refresh

we have had complaints from various budget holders in departments in the company that hardware refresh (e.g. end user kit, such as desktop/laptop) and software refresh programs (e.g. new versions of office) are often poorly communicated and "dropped" onto budget holders last minute and this doesnt allow them to properly budget year on year for these kind of exercises. Currently a bit unsure on what kind of process or policy should be in place to allow budget holders for forsee ICT costs to build into annual budget planning. How are your budget holders informed at your companies, what policies/processes do you have in place to keep them informed?