A natural reaction would be to rejoice momentarily, then leave the shares to continue their usual humdrum, unspectacular climb. But it might be better to regard that sudden burst as being highly vulnerable to a nasty correction, sell the stock for a nice profit, then buy it back when, hopefully, they have subsided a bit. This way you stick to the much-adored long haul system in principle, while still making the odd few pounds from dashing in and out the market according to its peaks and troughs. Remember that even the most reliable, stolid shares are pushed around by hopelessly unpredictable markets. So keep a weather eye open for any glaring chances to dip in and out.
All shoppers look for good value.
It's easy with potatoes. You can see what they look like and compare prices on other market stalls. It's a bit harder with toasters, washing machines and lawn mowers. And it's downright difficult with companies. Yet all City analysts look for 'good value' ie spiffing quality shares at rock-bottom prices.