A high wattage (input power) doesn't always mean better suction because the amount of this power that's turned into air watts (suction or output power) depends to some extent on the vacuum's design and efficiency.
When it comes to vacuuming small or awkward areas quickly and conveniently, there's nothing quite like a hand held vacuum. A cordless hand held vacuum cleaner knows no boundaries and with an endless list of uses, once you buy a hand held vacuum, you'll wonder how you ever lived without it.
The capacity of the vacuum cleaner's dust bin or bag will essentially determine how often you'll need to empty it. If you have a large house and you don't want to be going back and forth the bin, it's worth investing in a vacuum cleaner with a bigger capacity. That said, if you have trouble lifting or manoeuvring a vacuum cleaner, bear in mind that the bigger the vacuum cleaner's capacity, the heavier it'll be.