Read your contract before you do anything else
Find two things: the notice period and the renewal date. Thirty days is the most common notice period in commercial cleaning; sixty is not unusual. Auto-renewal clauses are also common, and the whole point of them is that you miss the window and owe another year.
Put the notice deadline in your calendar with a reminder two weeks before it. That single step is what separates people who change vendors when they want to from people who change vendors eventually.
Line up the replacement before you give notice
The order matters and most people get it backwards. Get the new company walked through, scoped and quoted, and have the start date agreed — then give notice. Giving notice first means negotiating under a deadline, which is how people end up with the second-best option at the first price they were offered.
A good incoming company will ask what went wrong with the last one. Answer honestly, including the parts that were your side. "They kept missing the third-floor restrooms" and "we never gave them a key that worked" lead to very different scopes.
The handover checklist
The week either side of the switch is where the mess happens. These are the things that reliably get forgotten:
- Keys, fobs and alarm codes returned by the outgoing crew, and reissued rather than handed over person to person.
- Alarm codes changed. Not because anyone is a thief, but because a code known to a company you no longer pay is a loose end.
- Building management told, and the new company added to the approved-contractor list. In a managed building this takes longer than anything else on this list.
- A certificate of insurance from the new company, naming you as additional insured, in your hands before the first visit.
- Consumables: who is holding the stock, and does the new company's first night include a restock?
- Equipment that belongs to the outgoing company removed, and anything that belongs to you kept.
Overlap by one night, not one month
The safest handover is a single night of overlap: the outgoing crew's last visit and the incoming crew's walkthrough on the same evening. The new crew sees the building in working condition, meets whoever locks up, and finds out where the janitor's closet actually is.
Paying two companies for a month is not caution, it is a way of never quite finishing the switch.
Expect the first two weeks to be bumpy
A new crew learns a building in about two weeks. The first few nights they will miss something you assumed was obvious, because it was obvious only to the people who had been doing it for three years.
Write those down as they happen and send them once, as a list, at the end of the first week. That is far more effective than five separate complaints, and it is how a scope gets accurate.