I think "as long as possible" is good.
: My son started walking at 9-10 months. I bought him shoes 7 months later for a vacation so he could wear them in the airport etc.
Indoors we still never wear shoes at home or elsewhere. [Is this cultural maybe? I actually thought no one was suppose to?] Outdoors in our back yard if its cold he wears slippers with heavy felt soles. [He's almost 3] Until he was 20 lbs [20 mo?] he was in a sling or stroller or back pack elsewhere in public with slippers or just socks. Since that first pair he only owned one pair of shoes at a time until last fall when we bought him water mocs for a vacation to a rock-barnacle beach.
Hubby owns [and wears] just about as many shoes as our son. I admit to owning dozens of dress shoes and sandals [it's a girl thing
for me], but wear sneakers flipflops or slippers Mon Thru Sat unless it's a holiday.
We figure Taylor didnt need shoes so why buy them. And we didnt/dont figure he needs many shoes so why buy them. I do think if he was a girl I would [regretfully] be different though if she asked me for dress shoes. Taylor did own/borrow a pair of the most wonderful dress shoes last summer for a wedding. He LOVED them and wanted to wear them ALL the time because they were just like Daddy's work shoes!!
As for new vs used, we only buy one pair at a time so we buy the most we can afford. If *I* wear used shoes *I* get blisters from the ex-toe marks. So if a used pair has toe marks NO WAY would I get them for my son. BUT if there are no toe [or heel] marks then used is such a better price!!
As for cheap vs expensive I think that mearly depends on fit [no matter what shoes must fit properly or they will cause trouble sooner or later] and if I can find a cheap pair that fits I will buy it [of course] but if I dont find one I eventually go to the kid shoe store at the mall and buy what ever does fit. Only caveat to that is durability. Now that he is 3 he is MUCH harder on shoes. We bought a cheaper pair last time and he actually wore them out before he out grew them?!?! So I do think we are going to have to rethink this... 1 pair $40 vs 2-3 pair $20
maybe expensive IS better in that case?