The phrase "are usually sufficient" is correct and usable in written English.
It can be used when discussing the adequacy or effectiveness of something in a general context.
Example: "In most cases, the provided resources are usually sufficient to complete the project on time."
Alternatives: "are generally adequate" or "tend to be enough."
"On red oak, two coats are usually sufficient," Ms. Dickel said.
Under U.S. law, the statements and activities recorded during stings are usually sufficient for prosecutors to file some combination of federal charges.
Compresses and topical treatments are usually sufficient for controlling the bleeding, although your doctor might suggest skipping your anticoagulant the day of the procedure.
On the other hand, simple wires are usually sufficient for SPI and I²C provided that all devices work at the same voltage.
We show that proximate factors consisting of 5-10% of the cross-sectional observations with the largest exposure are usually sufficient to almost perfectly replicate the population factors, even if these do not have a sparse structure.
I can toss off the chestnut, apple, and celery-root soup in Daniel Boulud's "Café Boulud" cookbook (if I buy the chestnuts cooked, peeled, and in a can) and have even produced a credible rémoulade; the moans and howls and alarming ouches that still punctuate my encounters with a chopping board and celeriac are usually sufficient to drive my husband from his study to finish the chopping for me.
One cut is usually sufficient, so that on the whole very little blood is drawn.
There was usually sufficient rainfall for their crops, and springs and seeps provided drinking water.
The intramedullary approach is usually sufficient to extract a cemented or cementless, well fixed, standard stem.
Once there is suspicion, a correct anamnesis and examination is usually sufficient.
The prescribed dose of Oxycontin, one tablet every twelve hours, is usually sufficient to relieve severe pain.
