A slow application is not always a radio problem
A video meeting stutters, a file takes a long time to load or an application responds slowly. It is tempting to call all of this bad Wi-Fi. The cause may be at several points: the device, wireless connection, local network, internet link or the service itself. Before ordering more access points, describe the actual symptoms. Which function is affected, when did the problem start and who can reproduce it reliably during ordinary work?
Collect comparable observations
Record the location, time, device and application involved. With the responsible team, check whether another device behaves similarly at the same location. Comparing a wired connection can provide useful clues when the same application and a comparable period are considered. Avoid changing several settings at once because any later difference will be difficult to attribute. A short, repeatable description is more useful to IT than a collection of unrelated speed tests performed under different conditions.
Consider radio conditions in context
Displayed signal strength is only part of the picture. Neighbouring wireless networks, changes to the building, busy radio resources and device capabilities may also matter. Cisco's site survey documentation discusses possible interference sources among other factors. For your own environment, IT should consider appropriate measurements alongside actual usage. Good coverage in an empty meeting room, for example, does not fully describe the experience of a larger group working there simultaneously with different devices and applications.
Check changes and close the loop
Once the cause is clearer, a targeted action can be planned. Afterwards, test the same application under conditions comparable to the original report. Record what changed and whether the original problem can still be reproduced. Include any remaining limitations in the feedback. This builds a dependable diagnosis step by step. Additional hardware may be useful, but it should follow the identified requirement rather than becoming the first response to every vague report about a slow connection somewhere in the building.
Further reading: Cisco: Wireless Site Survey FAQ.