If your baby's heading for six months (how did that happen so quickly?), it's time to start thinking about buying a highchair.
This is definitely a parental purchase worth making an effort over because your little one will scoff (or throw on the floor) three square meals a day in it for the next eighteen months or more.
Would you prefer your baby to sit right up at the dining table with you or do you favour a 'self-contained' highchair with its own tray to limit mess? If the former, ensure the seat height can be adjusted so your baby can reach the table. If you're not sure yet, some highchairs can be used either way.
Is the seat sufficiently supportive for a baby but roomy enough to last a toddler until they can sit in a normal chair? It's especially important that little ones who are just starting out on solids feel comfortable at mealtimes. For this reason, if you buy a wooden highchair, you might want to add an insert cushion; most ranges offer one although they're sometimes sold separately.
Will the highchair be reasonably easy to clean? Baby mealtimes are a messy business and your highchair will inevitably get smeared with all sorts of food. Avoid anything with too many nooks and crannies for squished up peas and the like to get lodged into and make sure all surfaces will be easy to wipe down. Trays can sometimes be removed and shoved in the dishwasher for a more thorough cleansing. Seat covers or cushions need to be washable or, better still, wipe-clean.
Does the highchair seem sturdy and safe? Specifically, look for a secure harness or d-rings so you can add one if you find your toddler thinks it's a superb idea to try and fling him or herself out of the highchair mid-meal (some do). A harness might also be needed to prevent them from slipping down between the seat and tray too (some models get round this by having a middle bar in the way).
Do you want the highchair to have a longer term use? 'Convertible' versions can be turned into toddler chairs or a small table and low chair. Consider though whether it would be cheaper just to buy this sort of thing separately later on - sometimes this is the case as convertible highchairs can be pricey. Also if you'll have a second baby, you might need a highchair for them anyway, so your older child won't get to use the dinky art desk or whatever it transforms into.
How big is your kitchen? If you're going to be tripping over the highchair because your kitchen or dining area is small, go for something relatively compact or a model which can be folded away easily between meals.
Do you care what it looks like? This might not be a priority for everyone but do bear in mind the highchair will be sitting in your kitchen for a good couple of years.
UPDATE:
The Antilop highchair from IKEA as featured in our round-up below has been recalled. The safety belts on Antilop highchairs made between July 2006 and November 2009, with the number 17389 underneath the seat are faulty. You can get a replacement safety belt free of charge at any IKEA store. To find your nearest store, visit Ikea.com.