Move-in certificates and building rules in Dubai
The practical sequence matters. Book the treatment after the previous tenant's furniture is out and before yours arrives, since empty units can be treated faster, more thoroughly and with shorter re-entry times. Ask the company to issue the certificate with the unit number, date, products used and technician details, and keep it with your tenancy papers. If you are moving out, some landlords deduct pest control from the deposit; a certificate from your own chosen provider is usually cheaper than the building's default arrangement.
Elsewhere in the UAE the certificate is less codified, but the logic holds. A pre-move-in treatment on an empty unit is the single best-value pest control purchase most tenants ever make, and it establishes a baseline: if pests appear later, the question of whether they predated your tenancy is already answered.